UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Statement [Abstract]
Revenue	$ 85,812,000	$ 70,870,000
Cost of revenue	14,645,000	12,639,000
Gross profit	71,167,000	58,231,000
Operating expenses
Sales and marketing	33,921,000	35,496,000
Research and development	17,304,000	13,880,000
General and administrative	18,474,000	18,640,000
Exit costs	0	983,000
Total operating expenses	69,699,000	68,999,000
Income (loss) from operations	1,468,000	(10,768,000)
Other income, net	3,639,000	1,705,000
Income (loss) before income taxes	5,107,000	(9,063,000)
Provision for income taxes	3,104,000	797,000
Net income (loss)	2,003,000	(9,860,000)
Net loss attributable to noncontrolling interest in consolidated subsidiary	(135,000)	0
Net income (loss) attributable to Semrush Holdings, Inc.	$ 2,138,000	$ (9,860,000)
Net income (loss) per share attributable to common stockholders
Net income (loss) attributable to Semrush Holdings, Inc. per share attributable to common stockholders—basic (in dollars per share)	$ 0.01	$ (0.07)
Net income (loss) attributable to Semrush Holdings, Inc. per share attributable to common stockholders—diluted (in dollars per share)	$ 0.01	$ (0.07)
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)	144,565,578	141,650,459
Weighted-average number of shares of common stock used in computing net income (loss) per share attributable to common stockholders—diluted (in shares)	147,697,501	141,650,459
Comprehensive income (loss)
Net income (loss)	$ 2,003,000	$ (9,860,000)
Other comprehensive income (loss)
Foreign currency translation adjustments	(485,000)	365,000
Unrealized loss on investments	(744,000)	(83,000)
Comprehensive income (loss)	774,000	(9,578,000)
Comprehensive loss attributable to noncontrolling interest in consolidated subsidiary	(135,000)	0
Comprehensive income (loss) attributable to Semrush Holdings, Inc.	$ 909,000	$ (9,578,000)