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 Class A Common Stock	Common Stock Class B Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit	Noncontrolling Interest
Redeemable Noncontrolling Interest, Beginning balance at Dec. 31, 2021	$ 0
Redeemable Noncontrolling Interest, Ending balance at Dec. 31, 2022	0
Beginning balance (in shares) at Dec. 31, 2021					31,841,061	108,870,126
Beginning balance at Dec. 31, 2021	225,542			$ 225,542	$ 0	$ 1	$ 264,871	$ (230)	$ (39,100)	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of Class B common stock to Class A common stock (in shares)					11,078,315	11,078,315
Issuance of common stock upon exercise of stock options (in shares)					681,860
Issuance of common stock upon exercise of stock options	981			981			981
Issuance of shares in connection with Employee Stock Purchase Plan (in shares)					64,756
Issuance of common stock in connection with Employee Stock Purchase Plan	758			758			758
Issuance of common stock upon vesting of restricted stock units (in shares)					77,182	51,759
Stock-based compensation expense	7,447			7,447			7,447
Cumulative translation adjustment	(851)			(851)				(851)
Unrealized gain (loss) on investments	(125)			(125)				(125)
Net income (loss)	(33,848)			(33,848)					(33,848)
Ending balance (in shares) at Dec. 31, 2022					43,743,174	97,843,570
Ending balance at Dec. 31, 2022	199,904			199,904	$ 0	$ 1	274,057	(1,206)	(72,948)	0
Redeemable Noncontrolling Interest, Ending balance at Dec. 31, 2023	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 (loss) on investments	3			3				3
Net income (loss)	950			950					950
Acquisition of additional noncontrolling shares	5,166									5,166
Ending balance (in shares) at Dec. 31, 2023		120,629,000	23,482,000		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
Issuance of common stock upon exercise of stock options (in shares)	1,534,375				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 (loss) on investments	116			116				116
Net income (loss)	8,236			8,236					8,236
Redeemable noncontrolling interest at redemption value	(978)			(978)			(978)
Reclassification of redeemable noncontrolling interest to noncontrolling interest	7,118									7,118
Net loss attributable to noncontrolling interest	(791)									(791)
Acquisition of additional noncontrolling shares	(1,745)									(1,745)
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