Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating activities
Net (loss) income	$ (42,273)	$ 3,063	$ (8,258)
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation and amortization	1,615	673	364
Stock-based compensation	29,880	5,380	4,826
Stock-based compensation in connection with vesting of Stock Appreciation Rights	2,847	0	0
Charitable donation of Class A common stock	13,107	0	0
Bad debt expense	364	614	164
Change in fair value of warrants	18,930	12,714	2,959
Loss on disposal of property and equipment	0	0	77
Deferred income tax benefit	(4,896)	0	0
Changes in operating assets and liabilities:
Accounts receivable	3,734	(31,526)	(7,230)
Contract assets	(96)	(130)	487
Prepaid expenses and other current assets	(2,837)	(158)	(263)
Deferred contract costs	(1,007)	(2,023)	(1,069)
Accounts payable	(6,820)	2,701	3,439
Accrued expenses and other current liabilities	1,603	29,294	5,572
Deferred rent	(232)	612	1,475
Unearned revenue	2,259	(446)	(121)
Other liabilities, noncurrent	75	0	0
Net cash provided by operating activities	16,253	20,768	2,422
Investing activities
Purchases of property and equipment, including capitalized software	(1,845)	(1,273)	(1,352)
Acquisition, net of cash acquired	(75,227)	0	0
Net cash used in investing activities	(77,072)	(1,273)	(1,352)
Financing activities
Proceeds from issuance of Class A common stock upon initial public offering, net of underwriting discounts	485,541	0	0
Cash received for employee payroll tax withholdings	46,956	0	0
Cash paid for employee payroll tax withholdings	(46,956)	(1,387)	0
Proceeds from line of credit	0	15,000	0
Repayment of line of credit	0	(18,500)	0
Proceeds from exercise of warrants	392	0	58
Payment of deferred finance costs	(136)	0	0
Payment of deferred offering costs	(4,124)	(2,154)	(143)
Proceeds from exercise of stock options and purchases under the employee stock purchase plan	17,835	2,601	310
Proceeds from issuance of preferred stock	0	50,000	0
Costs incurred from issuance of preferred stock	0	(234)	0
Net cash provided by financing activities	499,508	45,326	225
Net increase in cash and cash equivalents	438,689	64,821	1,295
Cash and cash equivalents, beginning of year	75,756	10,935	9,640
Cash and cash equivalents, end of year	514,445	75,756	10,935
Supplemental disclosure of cash flow information
Cash paid for income taxes, net	393	42	21
Cash paid for interest	0	157	214
Cash received for early exercise of stock options	0	561	0
Supplemental disclosure of non-cash investing and financing activities
Common stock issued in connection with acquisition	96,644	0	0
Fair value of substituted stock options granted in connection with acquisition	5,943	0	0
Exercise of warrants classified as liabilities	0	0	154
Accrued offering costs	345	348	147
Vesting of early exercised stock options	232	368	0
Accretion of redeemable convertible preferred stock to redemption value	14	70	136
Employee receivables for options exercised	0	23	132
Purchase of property and equipment	30	72	100
Capitalization of stock-based compensation for internal-use software	$ 288	$ 38	$ 17