CONSOLIDATED STATEMENTS OF REDEEMABLE NONCONTROLLING INTEREST AND STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Class A Common Stock	Class B Common Stock	Total Semrush Stockholders' Equity	Common Stock	Common Stock Class A Common Stock	Common Stock Class B Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Noncontrolling Interest
Redeemable Noncontrolling Interest, Beginning balance at Dec. 31, 2022	$ 0
Redeemable Noncontrolling Interest, Ending balance at Dec. 31, 2023	0
Beginning balance (in shares) at Dec. 31, 2022						43,743,174	97,843,570
Beginning balance at Dec. 31, 2022	199,904			$ 199,904		$ 0	$ 1	$ 274,057	$ (1,206)	$ (72,948)	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of Class B common stock to Class A common stock (in shares)						74,414,844	74,414,844
Conversion of Class B Common Stock to Class A Common Stock					$ 0	$ 1	$ (1)
Issuance of common stock upon exercise of stock options (in shares)						1,917,922
Issuance of common stock upon exercise of stock options	2,240			2,240				2,240
Issuance of shares in connection with Employee Stock Purchase Plan (in shares)						38,879
Issuance of common stock in connection with Employee Stock Purchase Plan	264			264				264
Issuance of common stock upon vesting of restricted stock units (in shares)						514,328	53,331
Stock-based compensation expense	15,337			15,337				15,337
Cumulative translation adjustment	451			451					451
Unrealized gain on investments	3			3					3
Net (loss) income	950			950						950
Acquisition of noncontrolling interest (See Note 9)	5,166										5,166
Ending balance (in shares) at Dec. 31, 2023						120,629,147	23,482,057
Ending balance at Dec. 31, 2023	224,315			219,149		$ 1	$ 0	291,898	(752)	(71,998)	5,166
Increase (Decrease) in Temporary Equity [Roll Forward]
Acquisition of redeemable noncontrolling interest (See Note 9)	9,846
Reclassification for Tender Offer obligations (See Note 9)	(3,636)
Redeemable noncontrolling interest at redemption value	978
Net loss attributable to redeemable noncontrolling interest	(70)
Reclassification of redeemable noncontrolling interest to noncontrolling interest	(7,118)
Redeemable Noncontrolling Interest, Ending balance at Dec. 31, 2024	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of Class B common stock to Class A common stock (in shares)						2,472,847	2,472,847
Conversion of Class B Common Stock to Class A Common Stock	0
Issuance of common stock upon exercise of stock options (in shares)						1,534,375
Issuance of common stock upon exercise of stock options	4,118			4,118				4,118
Issuance of common stock upon vesting of restricted stock units (in shares)						1,197,503
Stock-based compensation expense	27,548			27,548				27,548
Cumulative translation adjustment	(1,585)			(1,585)					(1,585)
Unrealized gain on investments	116			116					116
Redeemable noncontrolling interest at redemption value	(978)			(978)				(978)
Reclassification of redeemable noncontrolling interest to noncontrolling interest	7,118										7,118
Net (loss) income	8,236			8,236						8,236
Acquisition of additional noncontrolling shares	(1,745)										(1,745)
Net loss attributable to noncontrolling interest	(791)										(791)
Ending balance (in shares) at Dec. 31, 2024		125,834,000	21,009,000			125,833,872	21,009,210
Ending balance at Dec. 31, 2024	266,352			256,604		$ 1	$ 0	322,586	(2,221)	(63,762)	9,748
Redeemable Noncontrolling Interest, Ending balance at Dec. 31, 2025	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of Class B common stock to Class A common stock (in shares)						100,800	100,800
Issuance of common stock upon exercise of stock options (in shares)	1,203,565					1,092,157	111,408
Issuance of common stock upon exercise of stock options	$ 3,879			3,879				3,879
Issuance of common stock upon vesting of restricted stock units (in shares)						3,388,791
Payment of withholding taxes on net share settlements of restricted stock units (in shares)						(676,065)
Payment of withholding taxes on net share settlements of equity awards	(10,135)			(10,135)				(10,135)
Stock-based compensation expense	51,737			51,737				51,737
Reclassification of liability-classified awards to equity-classified awards	714			714				714
Cumulative translation adjustment	4,690			4,690					4,690
Unrealized gain on investments	18			18					18
Net (loss) income	(18,957)			(18,957)						(18,957)
Acquisition of additional noncontrolling shares	(6,763)										(6,763)
Net loss attributable to noncontrolling interest	(540)										(540)
Ending balance (in shares) at Dec. 31, 2025		129,740,000	21,020,000			129,739,555	21,019,818
Ending balance at Dec. 31, 2025	$ 290,995			$ 288,550		$ 1	$ 0	$ 368,781	$ 2,487	$ (82,719)	$ 2,445