CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Statement [Abstract]
Revenue	$ 307,675	$ 254,316	$ 188,001
Cost of revenue	52,327	48,553	41,934
Gross profit	255,348	205,763	146,067
Operating expenses
Sales and marketing	126,871	126,889	81,122
Research and development	57,442	41,204	24,322
General and administrative	77,410	62,779	43,116
Exit Costs	1,292	11,264	0
Total operating expenses	263,015	242,136	148,560
Loss from operations	(7,667)	(36,373)	(2,493)
Other income (expense), net	12,313	3,456	(522)
Income (loss) before income taxes	4,646	(32,917)	(3,015)
Provision for income taxes	3,696	931	270
Net income (loss)	950	(33,848)	(3,285)
Net income (loss) attributable to noncontrolling interest in consolidated subsidiary	0	0	0
Net income (loss) attributable to Semrush Holdings, Inc.	$ 950	$ (33,848)	$ (3,285)
Net income (loss) per share attributable to common stockholders
Net income (loss) per share attributable to common stockholders—basic (in dollars per share)	$ 0.01	$ (0.24)	$ (0.03)
Net income (loss) per share attributable to common stockholders—diluted (in dollars per share)	$ 0.01	$ (0.24)	$ (0.03)
Weighted-average number of shares of common stock used in computing net income (loss) per share attributable to common stockholders
Weighted-average number of shares of common stock used in computing net income (loss) per share attributable to common stockholders—basic (in shares)	142,593,000	141,160,000	126,586,000
Weighted-average number of shares of common stock used in computing net income (loss) per share attributable to common stockholders—diluted (in shares)	146,065,333	141,160,000	126,586,000
Net income (loss)	$ 950	$ (33,848)	$ (3,285)
Other comprehensive income (loss)
Foreign currency translation adjustments	451	(851)	(230)
Unrealized gain (loss) on investments	3	(125)	0
Comprehensive income (loss)	1,404	(34,824)	(3,515)
Comprehensive income attributable to noncontrolling interest in consolidated subsidiary	0	0	0
Comprehensive income (loss) attributable to Semrush Holdings, Inc.	$ 1,404	$ (34,824)	$ (3,515)