Vertex (VERX) 10-K 29 Feb 24 2023 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2023	Feb. 26, 2024	Jun. 30, 2023
Document Information:
Document Type	10-K
Document Period End Date	Dec. 31, 2023
Document Annual Report	true
Document Transition Report	false
Entity File Number	001-39413
Entity Registrant Name	Vertex, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	23-2081753
Entity Address, Address Line One	2301 Renaissance Blvd
Entity Address, City or Town	King of Prussia
Entity Address State Or Province	PA
Entity Address, Postal Zip Code	19406
City Area Code	800
Local Phone Number	355-3500
Title of 12(b) Security	Class A Common Stock, Par Value $0.001 Per Share
Trading Symbol	VERX
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Document Financial Statement Error Correction [Flag]	false
Entity Public Float			$ 835,566,225
Entity Central Index Key	0001806837
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Amendment Flag	false
Auditor Name	Crowe LLP
Auditor Location	New York, New York
Auditor Firm ID	173
Class A
Document Information:
Entity Common Stock, Shares Outstanding		61,673,585
Class B
Document Information:
Entity Common Stock, Shares Outstanding		92,661,000

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 68,175	$ 91,803
Funds held for customers	20,976	14,945
Accounts receivable, net of allowance of $16,272 and $9,554, respectively	141,752	102,885
Prepaid expenses and other current assets	26,173	22,340
Investment securities available-for-sale, at fair value (amortized cost of $9,550 and $11,220, respectively)	9,545	11,173
Total current assets	266,621	243,146
Property and equipment, net of accumulated depreciation	100,734	101,090
Capitalized software, net of accumulated amortization	38,771	39,012
Goodwill and other intangible assets	260,238	257,023
Deferred commissions	21,237	15,463
Deferred income tax asset	41,708	30,938
Operating lease right-of-use assets	14,605	17,187
Other assets	16,013	15,333
Total assets	759,927	719,192
Current liabilities:
Current portion of long-term debt	2,500	2,188
Accounts payable	23,596	14,329
Accrued expenses	44,735	38,234
Customer funds obligations	17,731	12,121
Accrued salaries and benefits	12,277	10,790
Accrued variable compensation	34,105	23,729
Deferred compensation, current		2,809
Deferred revenue, current	290,143	268,847
Current portion of operating lease liabilities	3,717	4,086
Current portion of finance lease liabilities	74	103
Deferred purchase consideration, current		19,824
Purchase commitment and contingent consideration liabilities, current	11,901	6,149
Total current liabilities	440,779	403,209
Deferred revenue, net of current portion	2,577	10,289
Debt, net of current portion	44,059	46,709
Operating lease liabilities, net of current portion	16,567	20,421
Finance lease liabilities, net of current portion	51	10
Purchase commitment and contingent consideration liabilities, net of current portion	2,600	8,412
Deferred other liabilities	313	417
Total liabilities	506,946	489,467
Commitments and contingencies (Note 15)
Stockholders' equity:
Preferred shares, $0.001 par value, 30,000 shares authorized; no shares issued and outstanding
Additional paid in capital	275,155	244,820
(Accumulated deficit) retained earnings	(586)	12,507
Accumulated other comprehensive loss	(21,742)	(27,752)
Total stockholders' equity	252,981	229,725
Total liabilities and stockholders' equity	759,927	719,192
Class A
Stockholders' equity:
Common stock	61	50
Class B
Stockholders' equity:
Common stock	$ 93	$ 100

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Allowance for accounts receivable	$ 16,272	$ 9,554
Amortized cost	$ 9,550	$ 11,220
Preferred stock par value (per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	30,000	30,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Class A
Common stock par value (per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock, shares issued (in shares)	60,989,000	50,014,000
Common stock, shares outstanding (in shares)	60,989,000	50,014,000
Class B
Common stock par value (per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	150,000,000	150,000,000
Common stock, shares issued (in shares)	92,661,000	100,307,000
Common stock, shares outstanding (in shares)	92,661,000	100,307,000

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenues:
Total revenues	$ 572,387	$ 491,624	$ 425,548
Cost of revenues:
Total cost of revenues	223,808	193,132	161,892
Gross profit	348,579	298,492	263,656
Operating expenses:
Research and development	58,212	41,877	44,018
Selling and marketing	140,237	125,335	99,005
General and administrative	145,936	121,651	107,009
Depreciation and amortization	15,202	12,440	11,678
Other operating expense , net	6,502	5,271	4,888
Total operating expenses	366,089	306,574	266,598
Loss from operations	(17,510)	(8,082)	(2,942)
Other (income) expense:
Interest expense, net	4,164	2,048	984
Loss before income taxes	(21,674)	(10,130)	(3,926)
Income tax expense (benefit)	(8,581)	2,174	(2,447)
Net loss	(13,093)	(12,304)	(1,479)
Other comprehensive (income) loss:
Foreign currency translation adjustments and revaluations, net of tax	(5,978)	10,219	14,370
Unrealized (gain) loss on investments, net of tax	(32)	36
Total other comprehensive (income) loss, net of tax	(6,010)	10,255	14,370
Total comprehensive loss	(7,083)	(22,559)	(15,849)
Software subscriptions
Revenues:
Total revenues	480,830	415,473	358,415
Cost of revenues:
Total cost of revenues	162,920	142,071	116,194
Services
Revenues:
Total revenues	91,557	76,151	67,133
Cost of revenues:
Total cost of revenues	60,888	51,061	45,698
Class A
Other comprehensive (income) loss:
Net loss attributable to stockholders, basic	$ (4,721)	$ (3,771)	$ (357)
Net loss per share, basic (in dollars per share)	$ (0.09)	$ (0.08)	$ (0.01)
Weighted average common stock, basic (in shares)	54,753	45,864	35,647
Net loss attributable to stockholders, diluted	$ (4,721)	$ (3,771)	$ (357)
Net loss per share, diluted (in dollars per share)	$ (0.09)	$ (0.08)	$ (0.01)
Weighted average common stock, diluted (in shares)	54,753	45,864	35,647
Class B
Other comprehensive (income) loss:
Net loss attributable to stockholders, basic	$ (8,372)	$ (8,533)	$ (1,122)
Net loss per share, basic (in dollars per share)	$ (0.09)	$ (0.08)	$ (0.01)
Weighted average common stock, basic (in shares)	97,106	103,781	112,133
Net loss attributable to stockholders, diluted	$ (8,372)	$ (8,533)	$ (1,122)
Net loss per share, diluted (in dollars per share)	$ (0.09)	$ (0.08)	$ (0.01)
Weighted average common stock, diluted (in shares)	97,106	103,781	112,133

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Common Stock Class A	Common Stock Class B	Additional Paid In Capital.	Retained Earnings (Accumulated Deficit) ASC 842	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive Income (Loss)	Class A	Class B	ASC 842	Total
Balance at Dec. 31, 2020	$ 26	$ 120	$ 206,541		$ 25,782	$ (3,127)				$ 229,342
Balance (in shares) at Dec. 31, 2020	26,327	120,117
Exercise of stock options, net	$ 3		(10,611)							(10,608)
Exercise of stock options, net (in shares)	2,157
Shares issued upon vesting of Restricted Stock Units, net			(78)							(78)
Shares issued upon vesting of Restricted Stock Units, net (in shares)	12
Shares issued upon vesting of Restricted Stock Awards, net			(213)							(213)
Shares issued upon vesting of Restricted Stock Awards, net (in shares)	352
Shares issued in connection with ESPP			2,060							2,060
Shares issued in connection with ESPP (shares)	128
Stock-based compensation expense			25,458							25,458
Distributions payable in connection with tax sharing agreement			(536)							(536)
Class B shares exchanged for Class A shares	$ 13	$ (13)
Class B shares exchanged for Class A shares (in shares)	13,310	(13,310)
Foreign currency translation adjustments and revaluations, net of tax						(14,370)				(14,370)
Net loss					(1,479)					(1,479)
Balance at Dec. 31, 2021	$ 42	$ 107	222,621	$ 508	24,811	(17,497)			$ 508	230,084
Balance (in shares) at Dec. 31, 2021	42,286	106,807
Exercise of stock options, net	$ 1		1,164							1,165
Exercise of stock options, net (in shares)	800
Shares issued upon vesting of Restricted Stock Units, net			(283)							(283)
Shares issued upon vesting of Restricted Stock Units, net (in shares)	48
Shares issued upon vesting of Restricted Stock Awards, net			(164)							(164)
Shares issued upon vesting of Restricted Stock Awards, net (in shares)	173
Shares issued in connection with ESPP			1,951							1,951
Shares issued in connection with ESPP (shares)	207
Stock-based compensation expense			19,531							19,531
Class B shares exchanged for Class A shares	$ 7	$ (7)
Class B shares exchanged for Class A shares (in shares)	6,500	(6,500)
Unrealized gain (loss) from available-for-sale investments, net of tax						(36)				(36)
Foreign currency translation adjustments and revaluations, net of tax						(10,219)				(10,219)
Net loss					(12,304)					(12,304)
Balance at Dec. 31, 2022	$ 50	$ 100	244,820		12,507	(27,752)				229,725
Balance (in shares) at Dec. 31, 2022	50,014	100,307					50,014	100,307
Exercise of stock options, net	$ 3		(29)							(26)
Exercise of stock options, net (in shares)	2,468
Shares issued upon vesting of Restricted Stock Units, net	$ 1		(4,690)							(4,689)
Shares issued upon vesting of Restricted Stock Units, net (in shares)	511
Shares issued upon vesting of Restricted Stock Awards, net			(146)							(146)
Shares issued upon vesting of Restricted Stock Awards, net (in shares)	198
Shares issued in connection with ESPP			2,486							2,486
Shares issued in connection with ESPP (shares)	152
Stock-based compensation expense			32,714							32,714
Class B shares exchanged for Class A shares	$ 7	$ (7)
Class B shares exchanged for Class A shares (in shares)	7,646	(7,646)
Unrealized gain (loss) from available-for-sale investments, net of tax						32				32
Foreign currency translation adjustments and revaluations, net of tax						5,978				5,978
Net loss					(13,093)					(13,093)
Balance at Dec. 31, 2023	$ 61	$ 93	$ 275,155		$ (586)	$ (21,742)				$ 252,981
Balance (in shares) at Dec. 31, 2023	60,989	92,661					60,989	92,661

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities:
Net loss	$ (13,093)	$ (12,304)	$ (1,479)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	71,891	61,153	44,782
Amortization of cloud computing implementation costs	2,570
Provision for subscription cancellations and non-renewals	2,083	(196)	466
Amortization of deferred financing costs	266	245	211
Write-off of deferred financing costs		370
Stock-based compensation expense	33,919	19,729	26,160
Deferred income tax benefit	(11,574)	(1,345)	(3,116)
Non-cash operating lease costs	2,587	3,357	3,825
Other	5,335	4,052	510
Changes in operating assets and liabilities:
Accounts receivable	(45,222)	(25,665)	2,962
Prepaid expenses and other current assets	(6,354)	(2,171)	(5,192)
Deferred commissions	(5,774)	(2,908)	(812)
Accounts payable	9,241	1,369	3,847
Accrued expenses	5,837	15,064	3,210
Accrued and deferred compensation	7,516	(12,005)	(3,735)
Deferred revenue	18,172	30,768	24,691
Operating lease liabilities	(4,224)	(4,041)	(4,697)
Other	1,156	(11,624)	(1,344)
Net cash provided by operating activities	74,332	63,848	90,289
Cash flows from investing activities:
Acquisition of business, net of cash acquired		(474)	(251,412)
Property and equipment additions	(49,261)	(45,532)	(31,706)
Capitalized software additions	(18,972)	(14,888)	(11,660)
Purchase of investment securities, available-for-sale	(16,328)	(16,518)
Proceeds from sales and maturities of investment securities, available-for-sale	18,390	5,364
Net cash used in investing activities	(66,171)	(72,048)	(294,778)
Cash flows from financing activities:
Net increase (decrease) in customer funds obligations	5,610	(11,340)	14,226
Proceeds from term loan		50,000
Principal payments on long-term debt	(2,188)	(938)
Payments for deferred financing costs	(1,001)	(983)
Proceeds from purchases of stock under ESPP	2,486	1,951	2,060
Payments for taxes related to net share settlement of stock-based awards	(9,701)	(1,104)	(12,758)
Proceeds from exercise of stock options	4,839	1,821	1,859
Distributions under Tax Sharing Agreement		(536)	(2,700)
Payments for purchase commitment and contingent consideration liabilities	(6,424)	(423)	(10,822)
Payments of finance lease liabilities	(103)	(1,354)	(964)
Payments for deferred purchase commitments	(20,000)	(20,000)
Net cash (used in) provided by financing activities	(26,482)	17,094	(9,099)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	724	(352)	(479)
Net (decrease) increase in cash, cash equivalents and restricted cash	(17,597)	8,542	(214,067)
Cash, cash equivalents and restricted cash, beginning of period	106,748	98,206	312,273
Cash, cash equivalents and restricted cash, end of period	$ 89,151	$ 106,748	$ 98,206

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Reconciliation of cash, cash equivalents and restricted cash to the Condensed Consolidated Balance Sheets, end of period:
Cash and cash equivalents	$ 68,175	$ 91,803	$ 73,333
Restricted cash-funds held for customers	20,976	14,945	24,873
Total cash, cash equivalents and restricted cash, end of period	$ 89,151	$ 106,748	$ 98,206

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2023
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	1. Nature of Business Vertex, Inc. (“Vertex”) and its consolidated subsidiaries and variable interest entities (“VIE”) (collectively, the “Company”) operate as solutions providers of state, local and value added tax calculation, compliance, and analytics, offering software products which are sold through software license and software as a service (“cloud”) subscriptions. The Company also provides implementation and training services in connection with its software license and cloud subscriptions, transaction tax returns outsourcing, and other tax-related services. The Company sells to customers located throughout the United States of America (“U.S.”) and internationally. Basis of Consolidation The consolidated financial statements are prepared in accordance with accounting principles generally accepted in the U.S. (“U.S. GAAP”) and include the accounts of the Company. All intercompany transactions have been eliminated in consolidation. The Company had an 80% and 65% controlling equity interest in Systax Sistemas Fiscais LTDA (“Systax”), a provider of Brazilian transaction tax content and software at December 31, 2023 and 2022, respectively. Systax was determined to be a VIE and the accounts are included in the consolidated financial statements. Vertex does not have full decision-making authority over Systax; however, Vertex is the entity that most significantly participates in the variability of the fair value of Systax’s net assets and is considered the entity most closely associated to Systax. As such, Vertex is deemed the primary beneficiary of Systax and consolidates Systax into its consolidated financial statements. Revision of Previously Issued Financial Statements ​ Certain prior period amounts on the consolidated balance sheets and consolidated statements of cash flows, reflected in the tables below, have been revised to correct for certain immaterial errors, as described below. During the second quarter of 2023, management identified certain immaterial errors impacting previously issued financial statements beginning as of December 31, 2021, and subsequent annual and quarterly reporting periods through March 31, 2023. Specifically, management identified an error in financial statement presentation required to be corrected to correctly reflect Cloud Computing Arrangement (“CCA”) software implementation costs in accordance with Accounting Standards Codification (“ASC”) 350-40, Goodwill and Other, Internal-Use Software Management assessed the materiality of this presentation on prior period consolidated financial statements in accordance with the Securities and Exchange Commission (“SEC”) Staff Accounting Bulletin No. 99, “Materiality,” codified in ASC 250, Accounting Changes and Error Corrections ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The consolidated balance sheets have been revised to reflect the correction as follows : ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 ​ As Reported ​ ​ Revision ​ ​ As Revised Property and equipment, net of accumulated depreciation $ 98,390 ​ $ (1,680) ​ $ 96,710 Other assets ​ 1,900 ​ ​ 1,680 ​ ​ 3,580 ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2022 (unaudited) ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment, net of accumulated depreciation $ 102,228 ​ $ (4,642) ​ $ 97,586 Other assets ​ 3,158 ​ ​ 4,642 ​ ​ 7,800 ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, 2022 (unaudited) ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment, net of accumulated depreciation $ 106,526 ​ $ (7,668) ​ $ 98,858 Other assets ​ 2,592 ​ ​ 7,668 ​ ​ 10,260 ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2022 (unaudited) ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment, net of accumulated depreciation $ 109,123 ​ $ (11,107) ​ $ 98,016 Other assets ​ 2,422 ​ ​ 11,107 ​ ​ 13,529 ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 ​ ​ ​ ​ ​ ​ ​ ​ Prepaid expenses and other current assets $ 20,383 ​ $ 1,957 ​ $ 22,340 Total current assets ​ 241,189 ​ ​ 1,957 ​ ​ 243,146 Property and equipment, net of accumulated depreciation ​ 115,768 ​ ​ (14,678) ​ ​ 101,090 Other assets ​ 2,612 ​ ​ 12,721 ​ ​ 15,333 ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2023 (unaudited) ​ ​ ​ ​ ​ ​ ​ ​ Prepaid expenses and other current assets $ 22,536 ​ $ 3,588 ​ $ 26,124 Total current assets ​ 231,435 ​ ​ 3,588 ​ ​ 235,023 Property and equipment, net of accumulated depreciation ​ 117,444 ​ ​ (17,942) ​ ​ 99,502 Other assets ​ 2,621 ​ ​ 14,354 ​ ​ 16,975 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The effect on the consolidated statements of cash flows are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Twelve months ended December 31, 2021 ​ ​ As Reported ​ ​ Revision ​ ​ As Revised Cash flows from operating activities: ​ ​ ​ ​ ​ ​ ​ ​ Other changes in operating assets and liabilities $ 336 ​ $ (1,680) ​ $ (1,344) Net cash (used in) provided by operating activities ​ 91,969 ​ ​ (1,680) ​ ​ 90,289 ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from investing activities: ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment additions ​ (33,386) ​ ​ 1,680 ​ ​ (31,706) Net cash used in investing activities ​ (296,458) ​ ​ 1,680 ​ ​ (294,778) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended March 31, 2022 (unaudited) ​ As Reported ​ ​ Revision ​ ​ As Revised Cash flows from operating activities: ​ ​ ​ ​ ​ ​ ​ ​ Other changes in operating assets and liabilities $ (950) ​ $ (2,962) ​ $ (3,912) Net cash (used in) provided by operating activities ​ 2,595 ​ ​ (2,962) ​ ​ (367) ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from investing activities: ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment additions ​ (13,873) ​ ​ 2,962 ​ ​ (10,911) Net cash used in investing activities ​ (17,259) ​ ​ 2,962 ​ ​ (14,297) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Six months ended June 30, 2022 (unaudited) ​ As Reported ​ ​ Revision ​ ​ As Revised Cash flows from operating activities: ​ ​ ​ ​ ​ ​ ​ ​ Other changes in operating assets and liabilities $ (457) ​ $ (5,988) ​ $ (6,445) Net cash (used in) provided by operating activities ​ 14,576 ​ ​ (5,988) ​ ​ 8,588 ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from investing activities: ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment additions ​ (27,827) ​ ​ 5,988 ​ ​ (21,839) Net cash used in investing activities ​ (41,170) ​ ​ 5,988 ​ ​ (35,182) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine months ended September 30, 2022 (unaudited) ​ As Reported ​ ​ Revision ​ ​ As Revised Cash flows from operating activities: ​ ​ ​ ​ ​ ​ ​ ​ Other changes in operating assets and liabilities $ (349) ​ $ (9,427) ​ $ (9,776) Net cash (used in) provided by operating activities ​ 33,026 ​ ​ (9,427) ​ ​ 23,599 ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from investing activities: ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment additions ​ (42,973) ​ ​ 9,427 ​ ​ (33,546) Net cash used in investing activities ​ (59,862) ​ ​ 9,427 ​ ​ (50,435) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Twelve months ended December 31, 2022 ​ ​ As Reported ​ ​ Revision ​ ​ As Revised Cash flows from operating activities: ​ ​ ​ ​ ​ ​ ​ ​ Prepaid expenses and other current assets $ (214) ​ $ (1,957) ​ $ (2,171) Other changes in operating assets and liabilities ​ (583) ​ ​ (11,041) ​ ​ (11,624) Net cash (used in) provided by operating activities ​ 76,846 ​ ​ (12,998) ​ ​ 63,848 ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from investing activities: ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment additions ​ (58,530) ​ ​ 12,998 ​ ​ (45,532) Net cash used in investing activities ​ (85,046) ​ ​ 12,998 ​ ​ (72,048) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended March 31, 2023 (unaudited) ​ As Reported ​ ​ Revision ​ ​ As Revised Cash flows from operating activities: ​ ​ ​ ​ ​ ​ ​ ​ Prepaid expenses and other current assets $ (2,109) ​ $ (1,631) ​ $ (3,740) Other changes in operating assets and liabilities ​ (58) ​ ​ (1,633) ​ ​ (1,691) Net cash (used in) provided by operating activities ​ 6,755 ​ ​ (3,264) ​ ​ 3,491 ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from investing activities: ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment additions ​ (13,313) ​ ​ 3,264 ​ ​ (10,049) Net cash used in investing activities ​ (17,561) ​ ​ 3,264 ​ ​ (14,297) ​ The consolidated balance sheet as of December 31, 2022 and the consolidated statements of cash flows for the years ended December 31, 2022 and 2021 have been revised in this Annual Report on Form 10-K. The Company intends to revise the remaining quarterly and annual amounts affected in future filings in which they appear, as applicable. Segments The Company operates its business as one operating segment. Operating segments are defined as components of an enterprise about which separate financial information is evaluated regularly by the chief operating decision maker (“CODM”), the Company’s Chief Executive Officer, in deciding how to allocate resources and assess performance. The Company’s CODM allocates resources and assesses performance based upon discrete financial information at the consolidated level. For the years ended December 31, 2023, 2022, and 2021 approximately 8%, 8%, and 7%, respectively, of the Company’s revenues were generated outside of the U.S. As of December 31, 2023 and 2022, $633 and $827 respectively, of the Company’s property and equipment assets were held outside of the U.S. Concentration of Credit Risk Financial instruments that potentially subject the Company to credit risk consist principally of cash and cash equivalents, which includes highly liquid investment securities, available-for-sale securities, funds held for customers and accounts receivable. The Company maintains the majority of its cash and cash equivalent balances and funds held for customers in four banks. These amounts exceed federally insured (“FDIC”) limits. The Company periodically evaluates the creditworthiness of the banks. The Company has not experienced any losses in these accounts and believes they are not exposed to significant credit risk on such accounts. The Company does not require collateral from its customers. Allowances are maintained for credit losses. Credit risk related to accounts receivable is limited due to the industry and geographic diversity within the Company's customer base. No single customer accounted for more than 10% of revenues for the years ended December 31, 2023, 2022, and 2021. Fair Value Measurement Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at a measurement date. A three-level fair value hierarchy (the “Fair Value Hierarchy”) prioritizes the inputs used to measure fair value. The Fair Value Hierarchy requires the Company to maximize the use of observable inputs and minimize the use of unobservable inputs. Classification in the Fair Value Hierarchy is based on the lowest of the following levels that is significant to the measurement: Level 1 Level 2 Level 3 The Company’s assessment of the significance of an input to a fair value measurement requires judgment, which may affect the determination of fair value and the measurement’s classification within the Fair Value Hierarchy. Use of Estimates The preparation of consolidated financial statements requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, equity, revenues, and expenses during the reporting period. Significant estimates used in preparing these consolidated financial statements include: (i) the estimated allowance for subscription cancellations; (ii) expected credit losses associated with the allowance for doubtful accounts; (iii) allowance for credit losses on available-for-sale debt securities; (iv) the reserve for self-insurance; (v) assumptions related to achievement of technological feasibility for software developed for sale; (vi) product life cycles; (vii) estimated useful lives and potential impairment of long-lived assets, intangible assets, and capitalized CCA software implementation costs; (viii) potential impairment of goodwill; (ix) determination of the fair value of tangible and intangible assets acquired, liabilities assumed, and consideration transferred in acquisitions; (x) amortization period of material rights and deferred commissions; (xi) Black-Scholes-Merton option pricing model (“Black-Scholes model”) input assumptions used to determine the fair value of certain stock-based compensation awards and Employee Stock Purchase Plan (“ESPP”) purchase rights; (xii) measurement of future purchase commitment, contingent consideration liabilities, and deferred purchase consideration liabilities associated with acquisitions; and (xiii) the potential outcome of future tax consequences of events that have been recognized in the consolidated financial statements or tax returns. Actual results may differ from these estimates. Cash and Cash Equivalents The Company considers all highly liquid investments purchased with an initial maturity date of three months or less to be cash equivalents. Funds held as investments in money market funds are included within cash and cash equivalents. In accordance with Accounting Standards Update (“ASU”) No. 2016-18, Restricted Cash Funds Held for Customers Funds held for customers in the consolidated balance sheets represents customer funds advanced for transaction tax returns outsourcing. Funds held for customers are restricted for the sole purpose of remitting such funds to satisfy obligations on behalf of such customers and are deposited at FDIC-insured institutions. Customer obligations are included in current liabilities in the consolidated balance sheets, as the obligations are expected to be settled within one year. Property and Equipment Property and equipment are stated at cost or fair value when acquired and presented net of accumulated depreciation. Normal maintenance and repairs are charged to expense, while major renewals and betterments are capitalized. Assets under finance leases are recorded at the present value of future lease payments. Assets under capital leases are recorded at the lower of the present value of the minimum lease payments or the fair value of the assets and are depreciated over the shorter of the asset’s useful life or lease term. ​ ​ Depreciation and amortization are computed straight-line over the estimated useful lives of the assets, as follows: ​ ​ ​ ​ Leasehold improvements 1 - 12 years Internal-use software developed 3 - 5 years Computer software purchased 3 - 7 years Equipment 3 - 10 years Furniture and fixtures 7 - 10 years ​ Software Development Costs Cloud Computing Software Implementation Costs ​ The Company follows ASC 350-40 to account for development costs incurred for cloud computing software implementations. ASC 350-40 requires such costs to be capitalized once certain criteria are met. Costs are primarily comprised of contracted labor, direct labor, and related expenses. ASC 350-40 includes specific guidance on costs not to be capitalized, such as overhead, general and administrative, and training costs. Costs are capitalized once the project is defined, funding is committed, and it is confirmed the software will be used for its intended use. Capitalization of these costs concludes once the project is substantially complete and the software is ready for its intended purpose. Post-configuration training and maintenance costs are expensed as incurred. ​ two ​ Amortization expense for capitalized cloud computing implementation costs for the year ended December 31, 2023 was $2,570 and is included in general and administrative expense in the consolidated statements of comprehensive loss. There was no amortization expense for the years ended December 31, 2022 or 2021. ​ Internal-Use Software The Company follows ASC 350-40 to account for development costs incurred for the costs of computer software developed or obtained for internal use. ASC 350-40 requires such costs to be capitalized once certain criteria are met. Capitalized internal-use software costs are primarily comprised of direct and contracted labor, and related expenses. ASC 350-40 includes specific guidance on costs not to be capitalized, such as overhead, general and administrative, and training costs. Internal-use software includes software utilized for cloud-based solutions as well as software for internal systems and tools. Costs are capitalized once the project is defined, funding is committed, and it is confirmed the software will be used for its intended use. Capitalization of these costs concludes once the project is substantially complete and the software is ready for its intended purpose. Post-configuration training and maintenance costs are expensed as incurred. Internal-use software is included in internal-use software developed in property and equipment in the consolidated balance sheets once available for its intended use. Depreciation expense for internal-use software utilized for cloud-based customer solutions and for software for internal systems and tools is included in cost of revenues, software subscriptions, and depreciation and amortization, respectively, in the consolidated statements of comprehensive loss. Software Developed for Sale The costs incurred for the development of computer software to be sold, leased, or otherwise marketed are capitalized in accordance with ASC 985-20, Costs of Software to be Sold, Leased or Marketed Amortization of capitalized software development costs begins when the product is available for general release. Amortization is provided on a product-by-product basis using the straight-line method over periods between three Capitalized software costs are subject to an ongoing assessment of recoverability based on anticipated future revenues and changes in software technologies at each balance sheet date. In the event of impairment, unamortized capitalized software costs are compared to the net realizable value of the related product and the carrying value of the related assets are written down to the net realizable value to the extent the unamortized capitalized costs exceed such value. The net realizable value is the estimated future gross revenues from the related product reduced by the estimated future costs of completing and disposing of such product, including the costs of providing related maintenance and customer support. Assessment of Long-Lived Assets The Company reviews the carrying value of long-lived assets, including internal-use software, for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be fully recoverable. Whenever such events or circumstances are present, an impairment loss equal to the excess of the asset carrying value over its fair value, if any, is recorded. Business Combinations Upon acquisition of a company, the Company determines if the transaction is a business combination, which is accounted for using the acquisition method of accounting. Under the acquisition method, once control is obtained of a business, the assets acquired, liabilities assumed, consideration transferred and amounts attributed to noncontrolling interests, are recorded at fair value. The Company uses its best estimates and assumptions to assign fair value to the tangible and intangible assets acquired, liabilities assumed, consideration transferred, and amounts attributed to noncontrolling interests at the acquisition date. One of the most significant estimates relates to the determination of the fair value of these amounts. The determination of the fair values is based on estimates and judgments made by management. The Company’s estimates of fair value are based upon assumptions it believes to be reasonable, but which are inherently uncertain and unpredictable. Measurement period adjustments to these values as of the acquisition date are reflected at the time identified, up through the conclusion of the measurement period, which is the time at which all information for determination of the values of assets acquired, liabilities assumed, consideration transferred, and noncontrolling interests is received, and is not to exceed one year from the acquisition date (the “Measurement Period”). Thus, the Company may record adjustments to the fair value of these tangible and intangible assets acquired, liabilities assumed, consideration transferred, and noncontrolling interests, with the corresponding offset to goodwill during this Measurement Period. Additionally, uncertain tax positions and tax-related valuation allowances are initially recorded in connection with a business combination as of the acquisition date. The Company continues to collect information and reevaluate these estimates and assumptions periodically and record any adjustments to preliminary estimates to goodwill, provided the Company is within the Measurement Period, with any adjustments to amortization of new or previously recorded identifiable intangibles being recorded to the consolidated statements of comprehensive loss in the period in which they arise. In addition, if outside of the Measurement Period, any subsequent adjustments to the acquisition date fair values are reflected in the consolidated statements of comprehensive loss in the period in which they arise. Goodwill Goodwill represents the excess of the purchase price over the fair value of net tangible and intangible assets acquired in a business combination. The Company evaluates goodwill for impairment annually at October 1 and whenever events or circumstances make it more likely than not that impairment may have occurred. The Company has determined that its business comprises one reporting unit. The Company has the option to first assess qualitative factors to determine whether events or circumstances indicate it is more likely than not that the fair value of a reporting unit is greater than its carrying amount, in which case a quantitative impairment test is not required. As provided for by ASU 2017-04, Simplifying the Test for Goodwill Impairment Deferred Financing Costs The Company capitalizes costs related to obtaining, renewing, or extending loan agreements and amortizes these costs on a straight-line basis, which approximates the effective interest method, over the life of the loan. Deferred financing costs related to undrawn debt are reflected in other assets in the consolidated balance sheets in accordance with ASC 835-30, Interest—Imputation of Interest Stock-Based Compensation The 2020 Incentive Award Plan (the “2020 Plan”) and the ESPP provide for the award of stock appreciation rights (“SARs”), stock options (“options”), restricted stock awards (“RSAs”), restricted stock units (“RSUs”), and participation in the ESPP (collectively, the “awards”). The awards are subject to, and the Company applies, the guidance set forth in ASC 718, Compensation—Stock Compensation The provisions of ASC 718 require a company to measure the fair value of stock-based compensation as of the grant date of the award. Stock-based compensation expense reflects the cost of employee services received in exchange for the awards. Stock-based compensation expense for stock options issued under the 2020 Plan is measured based on the grant date fair value of the award and is estimated using the Black-Scholes model. Compensation cost is recognized on a straight-line basis over the requisite service or performance period associated with the award. Stock-based compensation expense for RSAs and RSUs is based on the fair value of the Company’s underlying common stock on the date of grant. Compensation cost is recognized on a straight-line basis over the requisite service or performance period associated with the award. Stock-based compensation expense for awards subject to performance-based measurement criteria is recognized when achievement of performance targets is deemed probable. The ESPP permits participants to purchase Class A common stock through payroll deductions, up to a specified percentage of their eligible compensation. The plan is a compensatory plan as it allows participants to purchase stock at a 15% discount from the lower of the fair value of the Class A common on the first or last day of the ESPP offering period (the “ESPP Discount”). The ESPP is accounted for as an equity classified award. Stock-based compensation expense for the ESPP is measured based on the fair value of the ESPP award at the start of the offering period. The fair value is comprised of the value of the ESPP Discount and the value associated with the variability in the Class A common stock price during the offering period (the “Call/Put”), which is estimated using the Black-Scholes model. Compensation cost is recognized on a straight-line basis over the respective offering period. The Company has elected to recognize award forfeitures as they occur. Leases In accordance with ASU No. 2016-02, Leases For leases with terms greater than 12 months, the Company records an operating lease right-of-use asset or finance lease asset and related lease liability at the present value of lease payments over the lease term. The implicit rate for individual leases is generally not readily determinable; therefore, the Company uses its incremental borrowing rate at lease commencement to determine the present value of lease payments. Leases with an option to extend the related lease term or terminate early are reflected in the lease term when it is reasonably certain that the Company will exercise such options. The Company recognizes expense for operating leases on a straight-line basis over the lease term plus any variable lease costs. The Company does not recognize a right-of-use asset or lease liability for leases with an initial term equal to or less than 12 months (“short-term leases”) on its consolidated balance sheets. The Company recognizes expense on short-term leases in the consolidated statements of comprehensive loss on a straight-line basis over the lease term. Self-insurance The Company is self-insured for the majority of its health insurance costs, including medical claims subject to certain stop-loss provisions. Management periodically reviews the adequacy of the Company’s stop-loss insurance coverage. The Company records an estimate of claims incurred but not reported, based on management’s judgment and historical experience. Self-insurance accruals are $2,246 and $2,219 at December 31, 2023 and 2022, respectively, and are reflected in accrued salaries and benefits in the consolidated balance sheets. Material differences may result in the amount and timing of insurance expense if actual experience differs significantly from management’s estimates. Revenue Recognition Revenue from contracts with customers The Company recognizes revenue in accordance with ASC 606, Revenue from Contracts with Customers Nature of goods and services Licenses for on-premise software subscriptions, which are generally one year, provide the customer with a right to use the software as it exists when made available to the customer. Customers purchase a subscription to these licenses, which includes the related software and tax content updates and product support. The updates and support, which are part of the subscription agreement, are essential to the continued utility of the software; therefore, the Company has determined the software and the related updates and support to be a single performance obligation. Accordingly, when on-premise software is licensed, the revenue associated with this combined performance obligation is recognized ratably over the license term as these subscriptions are provided for the duration of the license term. Revenue recognition begins on the later of the beginning of the subscription period or the date the software is made available to the customer to download. Prior to January 1, 2022, certain on-premise software subscription prices in the initial subscription year were higher than standard renewal prices. The excess initial year price over the renewal price is a material right that provides customers with the right to this reduced renewal price. The Company recognizes revenue associated with this material right over the estimated period of benefit to the customer, which is generally three years. Effective January 1, 2022, the Company changed the pricing structure for on-premise software so the initial year price and renewal prices were consistent, thus removing the material right for transactions after this date. The material right for applicable transactions prior to this pricing change will continue to be recognized over the remaining estimated period of benefit to the customer. Cloud-based subscriptions allow customers to use Company-hosted software over the contract period without taking possession of the software. The cloud-based offerings also include related updates and support. Revenue recognition begins on the later of the beginning of the subscription period or the date the customer is provided access to the cloud-based solutions. Cloud-based contracts consistently provide a benefit to the customer during the subscription period; thus, the associated revenue is recognized ratably over the related subscription period. Revenue from deliverable-based services is recognized as services are delivered. Revenue from fixed fee services is recognized as services are performed using the percentage of completion input method. The Company has elected the “right to invoice” practical expedient for revenue related to services that are billed on an hourly basis, which enables revenue to be recognized as the services are performed. The Company has determined that the methods applied to measuring its progress toward complete satisfaction of performance obligations recognized over time are a faithful depiction of the transfer of control of software subscriptions and services to customers. Significant Judgments Contracts with customers often include promises to transfer multiple products and services to a customer. Determining whether products and services are considered distinct performance obligations that should be accounted for separately versus together may require significant judgment. Identification of the amortization periods of material rights and contract costs requires significant judgment by management. Payment Terms Payment terms and conditions vary by contract, although the Company’s terms generally include a requirement of payment within 30-60 days. In instances where the timing of revenue recognition differs from the timing of payment, the Company has determined that its contracts do not include a significant financing component. The primary purpose of invoicing terms is to provide customers with simplified and predictable ways of purchasing products and services, not to receive financing from customers or to provide customers with financing. Cost of Revenues Cost of revenues, software subscriptions include the direct cost to develop, host, and distribute software products, the direct cost to provide customer support, and amortization of costs capitalized for software developed for sale, for internal-use software utilized for cloud-based subscriptions and for certain acquired intangible assets. Cost of revenues, services include the direct costs of implementation, training, transaction tax returns outsourcing, and other tax-related services. Reimbursable Costs Reimbursable costs passed through and invoiced to customers of the Company are recorded as services revenues with the associated expenses recorded as cost of revenues, services in the consolidated statements of comprehensive loss. These amounts were $17, $133, and $14 for the years ended December 31, 2023, 2022, and 2021, respectively. Research and Development Research and development costs consist primarily of personnel and related expenses for research and development activities including salaries, benefits, and other compensation. Research and development costs are expensed as incurred in accordance with ASC 730, Research and Development, Advertising Advertising expense is recorded as incurred and is reflected in selling and marketing expense in the consolidated statements of comprehensive loss. Total advertising expense was $26,000, $26,529, and $20,386 for the years ended December 31, 2023, 2022, and 2021, respectively. Foreign Currency The Company transacts business in various foreign currencies. Management has concluded that the local country’s currency is the functional currency of its foreign operations. Consequently, operating activities outside the U.S. are translated into U.S. dollars using average exchange rates, while assets and liabilities of operations outside the U.S. are translated into U.S. dollars using exchange rates at the balance sheet date. The effects of foreign currency translation adjustments are included in total stockholders’ equ

REVENUE RECOGNITION

REVENUE RECOGNITION	12 Months Ended
	Dec. 31, 2023
REVENUE RECOGNITION
REVENUE RECOGNITION	2. Disaggregation of revenue The table reflects revenue by major source for the following periods: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2023 2022 2021 Software subscriptions: ​ ​ ​ ​ ​ ​ Software licenses ​ $ 266,213 ​ $ 246,577 ​ $ 231,371 Cloud subscriptions ​ ​ 214,617 ​ ​ 168,896 ​ ​ 127,044 Software subscriptions ​ ​ 480,830 ​ ​ 415,473 ​ ​ 358,415 Services ​ 91,557 ​ 76,151 ​ 67,133 Total revenues ​ $ 572,387 ​ $ 491,624 ​ $ 425,548 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contract balances Timing of revenue recognition may differ from the timing of invoicing customers. A receivable is recorded in the consolidated balance sheets when customers are billed related to revenue to be collected and recognized for subscription agreements as there is an unconditional right to invoice and receive payment in the future related to these subscriptions. A receivable and related revenue may also be recorded in advance of billings to the extent services have been performed and the Company has a right under the contract to bill and collect for such performance. Subscription-based customers are generally invoiced annually at the beginning of each annual subscription period. The Company’s payment terms typically range from 30-60 days. The beginning and ending balances of accounts receivable, net of allowance, are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2023 2022 Balance, beginning of period ​ $ 102,885 ​ $ 76,929 Balance, end of period ​ 141,752 ​ 102,885 Increase, net ​ $ 38,867 ​ $ 25,956 ​ A contract liability is recorded as deferred revenue on the consolidated balance sheets when customers are billed in advance of performance obligations being satisfied, and revenue is recognized after invoicing ratably over the subscription period or over the amortization period of material rights. Deferred revenue is reflected net of a related deferred allowance for subscription cancellations (the “deferred allowance”) of $11,741 and $7,133 at December 31, 2023 and 2022, respectively. The deferred allowance represents the portion of the allowance for subscription cancellations associated with deferred revenue. ​ The beginning and ending balances of and changes to the allowance and the deferred allowance are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2023 ​ 2022 ​ 2021 ​ ​ Balance ​ Net Change Balance ​ Net Change ​ Balance ​ ​ Net Change Allowance balance, January 1, ​ $ (9,554) ​ ​ $ (9,151) ​ $ (8,592) ​ ​ ​ Allowance balance, December 31, ​ (16,272) ​ ​ (9,554) ​ ​ (9,151) ​ ​ ​ Change in allowance ​ ​ ​ $ 6,718 ​ ​ ​ $ 403 ​ ​ ​ $ 559 Deferred allowance balance, January 1, ​ 7,133 ​ ​ 6,537 ​ ​ 6,432 ​ ​ ​ Deferred allowance balance, December 31, ​ 11,741 ​ ​ 7,133 ​ ​ 6,537 ​ ​ ​ Change in deferred allowance ​ ​ ​ (4,608) ​ ​ ​ (596) ​ ​ ​ ​ (105) Net amount charged to revenues ​ ​ ​ $ 2,110 ​ ​ ​ $ (193) ​ ​ ​ $ 454 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The amount of revenue recognized during the years ended December 31, 2023, 2022, and 2021 that was included in the opening deferred revenue balance of the same fiscal year was $268,847, $237,344, and $207,560, respectively. The portion of deferred revenue expected to be recognized in revenue beyond one year is included in deferred revenue, net of current portion in the consolidated balance sheets. The tables provide information about the balances of and changes to deferred revenue for the following periods: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ ​ 2023 ​ 2022 Balances: ​ ​ ​ Deferred revenue, current ​ $ 290,143 ​ $ 268,847 Deferred revenue, non-current ​ 2,577 ​ 10,289 Total deferred revenue ​ $ 292,720 ​ $ 279,136 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2023 ​ 2022 ​ 2021 Changes to deferred revenue: ​ ​ ​ Beginning balance ​ $ 279,136 ​ $ 249,010 ​ $ 222,262 Additional amounts deferred ​ 585,971 ​ 521,750 ​ 452,296 Revenues recognized ​ (572,387) ​ (491,624) ​ (425,548) Ending balance ​ $ 292,720 ​ $ 279,136 ​ $ 249,010 ​ Deferred revenue at December 31, 2023 will be recognized as follows for all future years: ​ ​ ​ ​ ​ Year Ending December 31, ​ ​ 2024 ​ $ 290,143 2025 ​ 2,498 2026 ​ 79 Total ​ $ 292,720 ​ Contract costs Deferred sales commissions earned by the Company’s sales force and certain sales incentive programs and vendor referral agreements are considered incremental and recoverable costs of obtaining a contract with a customer. An asset is recognized for these incremental contract costs and reflected as deferred commissions in the consolidated balance sheets. These contract costs are amortized on a straight-line basis over a period consistent with the transfer of the associated product and services to the customer, which is generally three years. Amortization of these costs are included in selling and marketing expense in the consolidated statements of comprehensive loss. The Company periodically reviews these contract assets to determine whether events or changes in circumstances have occurred that could impact the period of benefit of these assets. There were no impairment losses recorded for the periods presented. The changes to contract cost balances as of and for the following periods are: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2023 ​ 2022 ​ 2021 Deferred commissions: ​ ​ ​ Beginning balance ​ $ 15,463 ​ $ 12,555 ​ $ 11,743 Additions ​ 16,552 ​ 13,913 ​ 10,018 Amortization ​ (10,778) ​ (11,005) ​ (9,206) Ending balance ​ $ 21,237 ​ $ 15,463 ​ $ 12,555 3. ​ ​

BUSINESS COMBINATIONS

BUSINESS COMBINATIONS	12 Months Ended
	Dec. 31, 2023
BUSINESS COMBINATIONS
BUSINESS COMBINATIONS	3. LCR-Dixon On September 22, 2021, the Company executed a stock purchase agreement to acquire 100% of the stock of LCR-Dixon Corporation (“LCR-Dixon”), a provider of SAP technologies and tax intelligence solutions. LCR-Dixon’s solutions were specifically developed to improve functionality and performance for SAP indirect tax processes and are integrated with the Company’s tax determination software. The LCR-Dixon acquisition was accounted for as a business combination. The transaction costs associated with the acquisition were not significant. The purchase price was $99,062 as of the acquisition date consisting of (i) $59,720 of cash paid at closing, partially offset by $1,899 of LCR-Dixon cash received in the acquisition, resulting in net cash consideration at closing of $57,821, (ii) $474 cash paid related to the final determination of LCR-Dixon’s cash and net working capital as of the acquisition date (the “Post-closing Adjustment”) paid in January 2022, (iii) non-interest bearing deferred payments aggregating $40,000 to be paid in four equal installments of $10,000 every six-months beginning March 2022 and ending September 2023, net of a discount of $976 (the “deferred purchase consideration”), and (iv) other adjustments associated with income tax amounts that exceed the estimated amount calculated at closing of $156. Cash paid was funded from available cash on hand. The discount recorded as a reduction of the deferred purchase consideration will be recorded as interest expense over the payment period using the effective interest method. The deferred purchase consideration, net of discount, at December 31, 2023 and 2022 is $0 and $19,824, respectively and is included in current liabilities in the consolidated balance sheet. The following table summarizes the purchase price for LCR-Dixon: ​ ​ ​ ​ ​ ​ ​ As of Acquisition Date Cash consideration ​ $ 60,038 Fair value of deferred purchase consideration ​ ​ 39,024 Total ​ $ 99,062 ​ The purchase price was allocated to the net assets acquired based on management’s determination of their estimated fair values using available information as of the acquisition date. The excess of purchase consideration over the net assets acquired is recorded as goodwill, which primarily reflects the existence of intangible assets not recognized under U.S. GAAP such as the value of expected future synergies, the value of the assembled workforce and other market factors. Goodwill associated with the LCR-Dixon acquisition is not deductible for tax purposes. The fair values of these amounts on the acquisition date, which are reflected in the table below, were finalized during the second quarter of 2022 and include Measurement Period adjustments resulting in an increase to capitalized software of $7,700, an increase to other intangibles of $6,500 and various other adjustments resulting in a net reduction to goodwill of $11,178. Any subsequent adjustments to these values will be recorded in the consolidated statements of comprehensive loss in the period in which the adjustment is identified. ​ The Company and LCR-Dixon had a pre-existing relationship in the form of a royalty agreement at the acquisition date. The Company owed LCR-Dixon royalties in connection with licenses sold by the Company to end users when collected by the Company from end users (the “Royalty Agreement”). The Royalty Agreement terminated upon consummation of the acquisition and the Company wrote-off $252 of royalties payable to LCR-Dixon with an offset to goodwill. ​ The following table presents the allocation of the purchase price to the assets acquired and liabilities assumed as recorded in the Company’s consolidated balance sheet as of the acquisition date: ​ ​ ​ ​ ​ ​ ​ As of Acquisition Date Cash and cash equivalents ​ $ 1,899 Accounts receivable ​ ​ 1,586 Prepaid expenses and other current assets ​ ​ 150 Property and equipment ​ ​ 4 Capitalized software ​ ​ 7,700 Goodwill ​ ​ 86,639 Other intangibles ​ ​ 6,500 Accounts payable ​ ​ (19) Accrued expenses ​ ​ (202) Accrued compensation ​ ​ (1,746) Deferred income tax liability ​ ​ (3,630) Deferred revenue ​ ​ (71) Total ​ $ 98,810 ​ The fair value, valuation methodologies, estimated useful lives, and significant assumptions of the identifiable intangibles acquired in the LCR-Dixon acquisition are summarized in the table below: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 22, 2021 LCR-Dixon Identifiable Intangibles ​ Balance Sheet Location ​ ​ Fair Value ​ Valuation Methodology ​ Estimated Useful Life ​ Discount Rate ​ Trade name ​ Goodwill and other intangible assets (Note 9) ​ $ 200 ​ Relief from royalty method - income approach ​ 6 months ​ 20.0 % Customer relationships ​ Goodwill and other intangible assets (Note 9) ​ $ 6,300 ​ Excess earnings method - income approach ​ 3 years ​ 20.0 % Developed technology ​ Property and equipment, net (Note 6) ​ $ 7,700 ​ Relief from royalty method - income approach ​ 3 years ​ 20.0 % ​ ​ Taxamo ​ On May 12, 2021, the Company acquired 95% of the outstanding equity of EVAT Solutions Limited (“EVAT”) and its wholly owned subsidiaries (collectively “Taxamo”), a cloud-based provider of tax and payment automation for global eCommerce and marketplaces. This acquisition supports the Company’s growth strategies across eCommerce platforms and marketplaces in Europe and North America. Included in the acquisition agreement is an option to purchase from and an option for the remaining shareholder to sell the remaining 5% of the outstanding equity of EVAT (the “Option”) at a fixed amount between August and December 2021 for an estimated fair value of $10,034. ​ The purchase price for the Taxamo acquisition was $200,689, consisting of (i) $190,153 of cash paid at closing, partially offset by $2,662 of acquired cash, including $221 of restricted cash, received in the acquisition resulting in net cash consideration at closing of $187,491, (ii) an acquisition holdback with an estimated fair value upon acquisition of $502, and (iii) the Option. The Company recorded the estimated fair value of the Option payment amount in purchase commitment and contingent consideration liabilities, current, on the consolidated balance sheet as of the acquisition date. Cash consideration was funded from available cash on hand. ​ The following table summarizes the purchase price for Taxamo: ​ ​ ​ ​ ​ ​ ​ May 12, 2021 Cash paid at closing ​ $ 190,153 Fair value of acquisition holdback ​ 502 Fair value of the Option ​ ​ 10,034 Total ​ $ 200,689 ​ On August 19, 2021, the Company acquired the remaining 5% equity interest of EVAT for $10,034 through exercise of the Option, giving the Company 100% of the outstanding equity interest of EVAT. The acquisition holdback was fixed in Euros and approximated $468, which was paid during 2022. ​ The Taxamo acquisition was accounted for as a business combination. The purchase price was allocated to the net assets acquired based on management’s determination of their estimated fair values using available information as of the acquisition date. The excess of purchase consideration over the net assets acquired was recorded as goodwill, which reflects the value of intangible assets not recognized under U.S. GAAP such as the value of expected future synergies, the value of the assembled workforce and other market factors. The Company expects that goodwill associated with the Taxamo acquisition will not be deductible for tax purposes. Taxamo’s business and product offerings are being integrated into the Company’s one operating segment. ​ The following table presents the allocation of the purchase price to the assets acquired and liabilities assumed as recorded in the Company’s consolidated balance sheet as of the acquisition date: ​ ​ ​ ​ ​ ​ ​ May 12, 2021 Cash and cash equivalents ​ $ 2,441 Funds held for customers ​ ​ 221 Accounts receivable ​ ​ 2,657 Prepaid expenses and other current assets ​ ​ 908 Property and equipment ​ 40,792 Goodwill ​ ​ 164,199 Other intangibles ​ ​ 1,581 Accounts payable ​ ​ (304) Accrued expenses ​ ​ (1,395) Accrued compensation ​ ​ (3,939) Deferred revenue ​ ​ (2,196) Deferred other liabilities ​ ​ (4,276) Total ​ $ 200,689 ​ The fair value, valuation methodologies, estimated useful lives, and significant assumptions of the identifiable intangibles acquired in the Taxamo acquisition are summarized in the table below: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ May 12, 2021 Taxamo Identifiable Intangibles ​ Balance Sheet Location ​ ​ Fair Value ​ Valuation Methodology ​ Estimated Useful Life ​ Discount Rate ​ Developed technology ​ Property and equipment, net (Note 6) ​ $ 40,746 ​ Multi-period excess earnings method - income approach ​ 3 years ​ 16.5 % Trade name ​ Goodwill and other intangible assets (Note 9) ​ $ 608 ​ Relief from royalty method - income approach ​ 2 years ​ 16.5 % Customer relationships ​ Goodwill and other intangible assets (Note 9) ​ $ 973 ​ Distributor method - income approach ​ 2 years ​ 16.5 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The Company has included the financial results of Taxamo in the consolidated statement of comprehensive income (loss) from the date of acquisition. The transaction costs associated with the acquisition were $4,269 and are recorded in other operating expense, net, for the year ended December 31, 2021. ​ The Company assumed certain liabilities in the acquisition of Taxamo, including deferred revenue with a fair value of $2,196, using a cost-plus profit approach. The Company is amortizing the acquired deferred revenue at its fair value over the period for which it is incurring costs to support the assumed customer obligations. ​ Tellutax ​ On January 25, 2021, the Company executed an Asset Purchase Agreement with Tellutax LLC, a Portland, Oregon based edge computing technology startup (“Tellutax”), to acquire substantially all of Tellutax’s assets (the “Tellutax acquisition”). Cash consideration paid for the acquisition was $6,100, funded through cash on hand, and serves to strengthen the Company’s technology roadmap and hybrid cloud strategy enabling it to better serve customers in an increasingly hyper-connected environment. The Tellutax acquisition entitles the sellers to contingent consideration if sales targets are met during a period of time following the acquisition. ​ The Tellutax acquisition was accounted for as a business combination. The total purchase price was allocated to the net assets acquired based on management’s determination of their estimated fair values using available information as of the acquisition date. The excess of purchase consideration over the net assets acquired is recorded as goodwill, which primarily reflects the value of expected future synergies, the existence of intangible assets not recognized under U.S. GAAP such as the value of the assembled workforce and other market factors. The Company expects that goodwill associated with the Tellutax acquisition will be deductible for tax purposes. The fair values of these amounts on the acquisition date, which are reflected in the table below, have been finalized. Any subsequent adjustments to these values will be recorded in the consolidated statements of comprehensive income (loss) in the period in which the adjustment is identified. ​ The purchase price for the Tellutax acquisition included cash paid at closing plus an estimated fair value of contingent consideration of $2,200 (the “Tellutax Contingent Consideration”) as of January 25, 2021. The following table presents the final purchase price allocation recorded in the consolidated balance sheet as of the acquisition date: ​ ​ ​ ​ ​ ​ ​ January 25, 2021 Capitalized software - developed technology ​ $ 3,600 Goodwill ​ 4,700 Total ​ $ 8,300 ​ The Company has included the financial results of Tellutax in the consolidated statement of comprehensive income (loss) from the date of acquisition. ​ The fair value of developed technology was valued using the multi-period excess earnings method, which is a variation of the income approach. This method estimates an intangible asset’s value based on the present value of the incremental after-tax cash flows attributable to the intangible asset. The significant assumptions used in the developed technology valuation included an estimated linear obsolescence factor of 20% per year and a discount rate of 28.5%. ​ The fair value of Tellutax Contingent Consideration is estimated using a Monte Carlo Simulation to compute the expected cash flows from earnout payments specified in the purchase agreement. The Tellutax Contingent Consideration is based on three potential earn-out payments determined by periodic revenue achievements over a thirty-month period. Earnout payments have no maximum limit, but if certain targets are not met, there will be no earn-out payment for the applicable measurement period. The estimated fair value of the Tellutax Contingent Consideration recorded as of the acquisition date was $2,200. See Note 5 for information on recurring fair value adjustments after the acquisition date. ​ Unaudited Pro Forma Financial Information Unaudited proforma financial information has not been presented, as the information from the acquired companies would not have had a material impact individually or in the aggregate for the prior year periods. ​ Public Tender Offer and Withdrawal of Offer ​ On December 13, 2023, the Company announced that it had commenced a public tender offer to acquire a global provider of e-invoicing solutions. On January 14, 2024, the Company withdrew its public tender offer following competing offers. Total transaction costs of $4,853 associated with the public tender offer were expensed in 2023, and are reported in the other operating expense, net, line of the consolidated statement of comprehensive loss. ​ ​ ​

INVESTMENTS

INVESTMENTS	12 Months Ended
	Dec. 31, 2023
INVESTMENTS
INVESTMENTS	​ 4. INVESTMENTS The table below presents the amortized cost, gross unrealized gains and losses, allowance for credit losses, and fair value aggregated by major security type as of December 31, 2023 and 2022. Accrued interest receivables of $20 and $24 as of December 31, 2023 and 2022, respectively are not included in the tables. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2023 ​ Investment securities available-for-sale: ​ Amortized Cost Gross Unrealized Gain Gross Unrealized Loss ​ Allowance For Credit Losses Fair Value ​ Commercial Paper ​ $ 7,169 ​ $ — ​ $ (1) ​ $ — ​ $ 7,168 ​ U.S. Treasury Securities ​ ​ 3,628 ​ ​ — ​ ​ (7) ​ ​ — ​ ​ 3,621 ​ Total investment securities available-for-sale ​ $ 10,797 ​ $ — ​ $ (8) ​ $ — ​ $ 10,789 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2022 ​ Investment securities available for sale: ​ Amortized Cost Gross Unrealized Gain Gross Unrealized Loss ​ Allowance For Credit Losses Fair Value ​ Commercial paper ​ $ 9,662 ​ $ — ​ $ (2) ​ $ — ​ $ 9,660 ​ U.S. Treasury securities ​ ​ 5,249 ​ ​ — ​ ​ (46) ​ ​ — ​ ​ 5,203 ​ Total investment securities available for sale ​ $ 14,911 ​ $ — ​ $ (48) ​ $ — ​ $ 14,863 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Investment Securities in a Gross Unrealized Loss Position The table below provides the gross unrealized losses and fair value of securities available-for-sale aggregated by major security type and the length of time that individual securities have been in a continuous unrealized loss position as of December 31, 2023 and 2022. The amounts include securities available-for-sale without an allowance for credit losses. As of December 31, 2023, the Company’s available-for-sale investment securities consisted of 41 securities, 24 of which are in an immaterial unrealized loss position. As of December 31, 2022, the Company’s available-for-sale investment securities consisted of 52 securities, 39 of which are in an immaterial unrealized loss position. As a result, there is no allowance for credit losses recorded for available-for-sale debt securities as of December 31, 2023 or 2022. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2023 ​ ​ Less than 12 Months ​ 12 Months or Longer ​ Total Investment securities available-for-sale without an allowance for credit losses: ​ Fair Value Gross Unrealized Loss Fair Value ​ Gross Unrealized Loss Fair Value ​ Gross Unrealized Loss Commercial Paper ​ $ 4,472 ​ ​ (1) ​ $ — ​ $ — ​ $ 4,472 ​ $ (1) U.S. Treasury Securities ​ ​ — ​ ​ — ​ ​ 2,043 ​ ​ (7) ​ ​ 2,043 ​ ​ (7) Total investment securities available-for-sale ​ $ 4,472 ​ $ (1) ​ $ 2,043 ​ $ (7) ​ $ 6,515 ​ $ (8) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2022 ​ ​ Less than 12 Months ​ 12 Months or Longer ​ Total Investment securities available for sale without an allowance for credit losses: ​ Fair Value Gross Unrealized Loss Fair Value ​ Gross Unrealized Loss Fair Value ​ Gross Unrealized Loss Commercial paper ​ $ 6,464 ​ $ (4) ​ $ — ​ $ — ​ $ 6,464 ​ $ (4) U.S. Treasury securities ​ ​ 3,746 ​ ​ (27) ​ ​ 1,457 ​ ​ (19) ​ ​ 5,203 ​ ​ (46) Total investment securities available for sale ​ $ 10,210 ​ $ (31) ​ $ 1,457 ​ $ (19) ​ $ 11,667 ​ $ (50) ​ Maturities of Investment Securities The table below summarizes, as of December 31, 2023, the fair value of investment securities by major security type and contractual maturity as well as the total fair value, and amortized cost of investment securities by contractual maturity. Because borrowers may have the right to call or prepay certain obligations, the expected maturities of securities are likely to differ from the scheduled contractual maturities presented below. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2023 ​ ​ ​ Due in 1 Year or Less Due > 1 Year through 5 Years Due > 5 Years through 10 Years ​ Due > 10 Years Total ​ Fair value of investment securities available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial Paper ​ $ 7,168 ​ $ — ​ $ — ​ $ — ​ $ 7,168 ​ U.S. Treasury Securities ​ ​ 1,279 ​ ​ 2,342 ​ ​ — ​ ​ — ​ ​ 3,621 ​ Total investment securities available-for-sale ​ $ 8,447 ​ $ 2,342 ​ $ — ​ $ — ​ $ 10,789 ​ Amortized cost of investment securities available-for-sale ​ $ 8,450 ​ $ 2,347 ​ $ — ​ $ — ​ $ 10,797 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The Company’s debt securities portfolio had unaccreted discounts of $114 and $139 and had no remaining unamortized premiums as of December 2023 and 2022, respectively. Net Securities Gains or Losses and Securities Pledged ​ During 2023, the Company had sales of debt securities totaling $2,336, resulting in a realized loss of $4. During 2022, the Company had no sales of debt securities categorized as available-for-sale, resulting in no realized gain or (loss). No securities were pledged during the years ended December 31, 2023 or 2022. ​ During the years ended December 31, 2023 and 2022, no net gains or losses were recognized on sales of equity securities and no unrealized gains or losses were recognized on equity securities held as of December 31, 2023 or 2022.

FINANCIAL INSTRUMENTS AND FAIR

FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS	12 Months Ended
	Dec. 31, 2023
FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS
FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS	5 . Financial instruments and fair value measurements Assets and Liabilities Measured at Fair Value on a Recurring Basis The following table summarizes the Company’s fair value for its financial assets and liabilities measured at fair value on a recurring basis: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements Using As of December 31, 2023 ​ Fair Value Prices in active markets for identical assets (Level 1) Significant other observable inputs (Level 2) Significant unobservable inputs (Level 3) Money Market Funds ​ $ 53,049 ​ $ 53,049 ​ $ — ​ $ — Commercial Paper ​ ​ 7,168 ​ ​ — ​ ​ 7,168 ​ ​ — U.S. Treasury Securities ​ ​ 3,621 ​ ​ — ​ ​ 3,621 ​ ​ — Tellutax Contingent Consideration ​ ​ 4,900 ​ ​ — ​ ​ — ​ ​ 4,900 Foreign Currency Forward Contracts ​ ​ 849 ​ ​ — ​ ​ 849 ​ ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements Using As of December 31, 2022 ​ Fair Value Prices in active markets for identical assets (Level 1) Significant other observable inputs (Level 2) Significant unobservable inputs (Level 3) Money Market Funds ​ $ 67,430 ​ $ 67,430 ​ $ — ​ $ — Commercial Paper ​ ​ 9,660 ​ ​ — ​ ​ 9,660 ​ ​ — U.S. Treasury Securities ​ ​ 5,203 ​ ​ — ​ ​ 5,203 ​ ​ — Tellutax Contingent Consideration ​ ​ 4,800 ​ ​ — ​ ​ — ​ ​ 4,800 Foreign Currency Forward Contracts ​ ​ 569 ​ ​ — ​ ​ 569 ​ ​ — ​ The Company has investments in Money Market Funds, which are included in cash and cash equivalents on the consolidated balance sheets. Fair value inputs for these investments are considered Level 1 measurements within the Fair Value Hierarchy since Money Market Fund fair values are known and observable through daily published floating net asset values. Securities classified as available-for-sale are reported at fair value using Level 2 inputs. For the Commercial Paper and U.S. Treasury Securities, the Company believes that Level 2 designation is appropriate under ASC 820-10, Fair Value Measurements and Disclosures Tellutax Contingent Consideration The Tellutax acquisition entitled the sellers to contingent consideration if sales targets are met during a period of time following the acquisition. The estimated fair value of the Tellutax Contingent Consideration as of the acquisition date of January 25, 2021 was $2,200. The Tellutax Contingent Consideration is based on three potential earn-out payments determined by periodic revenue achievements over a thirty-month period. Such estimate represents a recurring fair value measurement with significant unobservable inputs, which management considers to be Level 3 measurements under the Fair Value Hierarchy. The significant assumptions used in these calculations included forecasted results and the estimated likelihood for each performance scenario. The fair value of Tellutax Contingent Consideration is estimated using a Monte Carlo Simulation to compute the expected cash flows from earn-out payments specified in the purchase agreement. The Tellutax Contingent Consideration is based on three potential earn-out payments determined by periodic revenue achievements over a thirty-month period. Earn-out payments have no maximum limit, but if certain targets are not met, there will be no earn-out payment for the applicable measurement period. An adjustment to the Tellutax Contingent Consideration fair value of $1,549 and $2,300 was recorded in other operating expense, net for the years ended December 31, 2023 and 2022, respectively. At December 31, 2023, the Tellutax Contingent Consideration of $2,300 and $2,600 is included in purchase commitment and contingent consideration liabilities, current, and purchase commitment and contingent consideration liabilities, net of current portion, respectively, in the consolidated balance sheets. At December 31, 2022, the Tellutax Contingent Consideration of $1,400 and $3,400 is included in purchase commitment and contingent consideration liabilities, current, and purchase commitment and contingent consideration liabilities, net of current portion, respectively, in the consolidated balance sheets. Tellutax Contingent Consideration fair value and unobservable inputs used for the Monte Carlo Simulation valuation were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2023 Liability Fair Value Valuation Technique Unobservable Inputs Tellutax Contingent Consideration ​ $ 4,900 ​ Monte Carlo Simulation ​ Revenue volatility ​ 60.0 % ​ ​ ​ ​ ​ ​ ​ Revenue discount rate ​ 20.8 % ​ ​ ​ ​ ​ ​ ​ Term (in years) ​ 1.3 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 Liability Fair Value Valuation Technique Unobservable Inputs Tellutax Contingent Consideration ​ $ 4,800 ​ Monte Carlo Simulation ​ Revenue volatility ​ 75.0 % ​ ​ ​ ​ ​ ​ ​ Revenue discount rate ​ 22.4 % ​ ​ ​ ​ ​ ​ ​ Term (in years) ​ 2.4 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Beginning and ending balances in fair value of Tellutax Contingent Consideration were as follows: ​ ​ ​ ​ ​ ​ ​ Tellutax ​ ​ Contingent ​ ​ Consideration ​ ​ ​ Balance, January 1, 2021 ​ $ — Acquisition of Tellutax ​ ​ 2,200 Fair value adjustments ​ ​ 300 Balance, December 31, 2021 ​ ​ 2,500 Fair value adjustments ​ ​ 2,300 Balance, December 31, 2022 ​ ​ 4,800 Fair value adjustments ​ ​ 1,549 Payments ​ ​ (1,449) Balance, December 31, 2023 ​ $ 4,900 ​ Assets and Liabilities for Which Fair Value is Only Disclosed The carrying amounts of cash and cash equivalents and the carrying amount of funds held for customers were the same as their respective fair values and are considered Level 1 measurements. The carrying amount of our bank debt approximates fair value as the variable rates on the debt approximate those commercially available in the market, and is considered a Level 3 measurement. Non-recurring Fair Value Measurements The LCR-Dixon acquisition on September 22, 2021, the Taxamo acquisition on May 12, 2021, the Tellutax acquisition on January 25, 2021, and the Systax acquisition on January 10, 2020, were accounted for as business combinations and the total purchase price for each acquisition was allocated to the net assets acquired and liabilities assumed based on their estimated fair values. The LCR-Dixon deferred purchase consideration of $0 and $19,824 (See Note 3) are recorded in the consolidated balance sheets at December 31, 2023 and 2022, respectively. The carrying amount approximated its respective fair value at December 31, 2022 and is considered a Level 3 non-recurring fair value measurement. ​ On January 7, 2020, the Company acquired a 60% controlling interest in Systax, a provider of Brazilian transaction tax content and software. The Company has a contractual commitment to acquire the remaining equity interest from the original Systax quotaholders incrementally through 2024. Future purchase commitment payments for these incremental acquisition amounts are based on a multiple of Systax revenue and earnings before interest, depreciation, amortization, and income taxes (“EBITDA”) performance at the end of 2022 and 2023, whereby the Company will have full ownership after the final transaction in 2024. Management determined these future purchase commitments to be a forward contract, resulting in the Company being required to estimate and record an estimated future purchase commitment amount (the “Purchase Commitment Liability”) in connection with recording the initial purchase. The fair value of the Purchase Commitment Liability at the acquisition date was finalized to be $12,592. This amount will fluctuate as a result of changes in foreign currency exchange rates and is reflected in purchase commitment and contingent consideration liabilities in the consolidated balance sheets, with such changes in exchange rates being reflected in other comprehensive loss or income in the consolidated statements of comprehensive loss. Adjustments to the settlement date value that arise as a result of remeasurement at future balance sheet dates will be recorded as interest expense related to financing costs in the consolidated statements of comprehensive income (loss) in the period the change is identified. The Company recorded increases in interest expense of $4,022 and $990, during 2023 and 2022, respectively, associated with recording an increase in the settlement value. ​ The Company acquired an additional 5% equity interest of Systax during 2021 for $788, increasing the Company’s equity interest in Systax to 65%. The Company acquired an additional 15% equity interest of Systax through a Purchase Commitment Liability payment of $4,975 during 2023, increasing the Company’s equity interest in Systax to 80%. The remaining Purchase Commitment Liability at December 31, 2023 included in purchase commitment and contingent consideration liabilities, current, in the consolidated balance sheet was $9,601. The Purchase Commitment Liability included in purchase commitment and contingent consideration liabilities, current and purchase commitment and contingent consideration liabilities, net of current portion in the consolidated balance sheets on December 31, 2022 was $4,749 and $5,012, respectively. The carrying amounts approximated their respective fair values at December 31, 2023 and 2022, respectively, and are considered Level 3 non-recurring fair value measurements. The Company’s obligation with respect to future purchase commitments to the original Systax Quotaholders was determined to be a forward contract necessitating initial recognition based on fair value. The Company estimated the initial fair value of the Purchase Commitment Liability using a Monte Carlo Simulation, which the Company considers to be a Level 3 measurement. The significant assumptions used in the Monte Carlo Simulation include, among other variables, forecasted cash flow projections consistent with those used to support the overall purchase price, selection of comparable companies, asset volatility and discount rate determinations, and the total number of simulations to compute. Subsequent remeasurements of the Purchase Commitment Liability, as and if required, are not expected to be based on fair value. Derivative Instruments The Company may periodically enter into derivative contracts to reduce its exposure to foreign currency exchange rates. Historically the Company has not designated derivative contracts as hedges. The derivative contracts are typically designed to manage specific risks according to the Company’s strategies, which may change from time to time. In May 2020, the Company entered into a series of foreign currency forward contracts to reduce its exposure to adverse fluctuations in the Brazilian Real associated with a portion of the Purchase Commitment Liability. Such forward contracts, have not been designated as a hedge, do not qualify for hedge accounting and are not material to the consolidated financial statements. The Company remeasures these forward contacts at fair value on a recurring basis and include them in other assets in the consolidated balance sheets with changes in their estimated fair value recognized as interest expense in the consolidated statements of comprehensive loss. The Company’s fair value determinations are based on foreign currency exchange rates in active markets, which the Company considers to be Level 2 measurements within the Fair Value Hierarchy.

PROPERTY AND EQUIPMENT

PROPERTY AND EQUIPMENT	12 Months Ended
	Dec. 31, 2023
PROPERTY AND EQUIPMENT
PROPERTY AND EQUIPMENT	6 . PROPERTY AND EQUIPMENT The major components of property and equipment are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ ​ 2023 ​ 2022 ​ ​ ​ ​ ​ Leasehold improvements ​ $ 20,662 ​ $ 20,929 Equipment ​ 22,012 ​ 39,238 Computer software purchased ​ 2,690 ​ 11,892 Internal-use software developed: ​ ​ ​ ​ Cloud-based customer solutions ​ 142,302 ​ 142,980 Internal systems and tools ​ 39,430 ​ 42,035 Furniture and fixtures ​ 7,669 ​ 7,665 In-process internal-use software ​ 28,883 ​ 18,200 Property and equipment ​ 263,648 ​ 282,939 Less accumulated depreciation and amortization ​ (162,914) ​ (181,849) Property and equipment, net ​ $ 100,734 ​ $ 101,090 ​ Depreciation expense for property and equipment, excluding all internal-use software developed and finance leases, was $5,847, $6,445, and $7,425 for the years ended December 31, 2023, 2022, and 2021, respectively. Depreciation for property and equipment, excluding internal-use software developed for cloud-based customer solutions, is reflected in depreciation and amortization in the consolidated statements of comprehensive loss. Finance lease amortization was $610, $1,082, and $931 for the years ended December 31, 2023, 2022, and 2021, respectively. Finance lease amortization is included in depreciation and amortization in the consolidated statements of comprehensive loss. Assets under finance leases of $297, and $1,461, net of accumulated amortization of $190 and $861, at December 31, 2023 and 2022, respectively, are included in property and equipment in the consolidated balance sheets. The major components of internal-use software developed are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ ​ 2023 ​ 2022 ​ ​ ​ ​ Internal-use software developed ​ $ 181,732 ​ $ 185,015 Less accumulated depreciation ​ (121,646) ​ (119,603) Internal-use software developed, net of accumulated depreciation ​ 60,086 ​ 65,412 In-process internal-use software ​ 28,883 ​ 18,200 Internal-use software developed, net ​ $ 88,969 ​ $ 83,612 ​ Amounts included in property and equipment additions related to capitalized internal-use software on the consolidated statements of cash flows are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2023 ​ 2022 ​ 2021 Cloud-based customer solutions $ 29,496 $ 28,918 $ 19,837 Internal systems and tools 17,751 ​ 13,356 ​ 9,811 Total $ 47,247 ​ $ 42,274 ​ $ 29,648 ​ In-process internal-use software developed is not depreciated until it is available for its intended use. Depreciation expense for internal-use software developed for cloud-based customer solutions for the years ended December 31, 2023, 2022, and 2021, was $34,592, $27,682, and $19,076, respectively, and is included in cost of revenues, software subscriptions in the consolidated statements of comprehensive loss. Developed technology with an acquisition date fair value of $40,746 was recorded in connection with the Taxamo acquisition and is reflected in property and equipment, net, in the consolidated balance sheets at December 31, 2022. Depreciation expense for the years ended December 31, 2023, 2022, and 2021 associated with this developed technology was $12,325, $11,770, and $8,123, respectively, and is reflected in cost of revenues - software subscriptions in the consolidated statement of comprehensive loss. Depreciation expense for internal-use software developed for internal systems and tools for the years ended December 31, 2023, 2022, and 2021 was $8,745, $4,913, and $3,322, respectively, and is included in depreciation and amortization in the consolidated statements of comprehensive loss. Amortization expense of internal-use software developed, excluding in-process internal-use software not yet available for its intended use, at December 31, 2023 is as follows for all future years: ​ ​ ​ ​ ​ ​ ​ ​ Year Ending December 31, Internal Systems and Tools Cloud-Based Customer Solutions 2024 ​ $ 8,982 ​ $ 25,151 2025 ​ 6,787 ​ ​ 12,822 2026 ​ 1,615 ​ ​ 3,901 2027 ​ 621 ​ ​ — 2028 ​ 207 ​ ​ — Total ​ $ 18,212 ​ $ 41,874 ​

CAPITALIZED SOFTWARE

CAPITALIZED SOFTWARE	12 Months Ended
	Dec. 31, 2023
CAPITALIZED SOFTWARE
CAPITALIZED SOFTWARE	7. Capitalized software includes acquired software and direct labor and related expenses for software developed for sale for new products and enhancements to existing products. The major components of capitalized software are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ 2023 ​ 2022 Capitalized software ​ $ 115,152 ​ $ 96,577 Less accumulated amortization ​ (81,410) ​ (62,197) Capitalized software, net of accumulated depreciation ​ 33,742 ​ 34,380 In-process capitalized software ​ 5,029 ​ 4,632 Capitalized software, net ​ $ 38,771 ​ $ 39,012 ​ Software development costs capitalized for the years ended December 31, 2023, 2022, and 2021, excluding acquisitions were $18,972, $14,888, and $11,660, respectively. Capitalized software includes developed technology with an acquisition date fair value of $7,700, in connection with finalizing our purchase price acquisition allocation of the LCR-Dixon acquisition and was recorded during the year ended December 31, 2022. Capitalized software amortization expense, including amortization of acquired technology for the years ended December 31, 2023, 2022, and 2021 was $19,213, $17,018, and $12,962, respectively, and is included in cost of revenues, software subscriptions in the consolidated statements of comprehensive loss. Amortization expense associated with the acquired LCR-Dixon developed technology from the acquisition date through December 31, 2022 was $3,208 and is included in the capitalized software amortization expense for the year ended December 31, 2022. Included in this amount is $642 that would have been recorded during the year ended December 31, 2021 had the fair value of acquired LCR-Dixon developed technology been available on the acquisition date. In-process capitalized software at December 31, 2023 was not available for general release to customers as of the balance sheet date and therefore not included in the table below. Amortization expense of capitalized software available for general release to customers as of December 31, 2023 is as follows for all future years: ​ ​ ​ ​ ​ Year Ending December 31, ​ 2024 ​ $ 19,143 2025 ​ 10,689 2026 ​ 3,880 2027 ​ 30 2028 ​ — Total ​ $ 33,742 ​

LEASES

LEASES	12 Months Ended
	Dec. 31, 2023
LEASES
LEASES	8. The Company leases office space, IT equipment and office equipment. The Company’s leases have remaining terms of up to 5 years. The following table sets forth the Company’s lease assets and liabilities and their balance sheet location as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ Balance Sheet Location ​ 2023 2022 Lease assets: ​ ​ ​ ​ ​ ​ Operating lease right-of-use assets ​ Operating lease right-of-use assets ​ $ 14,605 ​ $ 17,187 Finance lease assets ​ Property and equipment, net (Note 6) ​ ​ 107 ​ ​ 600 Total lease assets ​ ​ ​ $ 14,712 ​ $ 17,787 ​ ​ ​ ​ ​ ​ ​ ​ ​ Lease liabilities: ​ ​ ​ ​ ​ ​ ​ ​ Current: ​ ​ ​ ​ ​ ​ ​ ​ Operating lease liabilities ​ Current portion of operating lease liabilities ​ $ 3,717 ​ $ 4,086 Finance lease liabilities ​ Current portion of finance lease liabilities ​ ​ 74 ​ ​ 103 Total current lease liabilities ​ ​ ​ $ 3,791 ​ $ 4,189 Non-current: ​ ​ ​ ​ ​ ​ ​ ​ Operating lease liabilities ​ Operating lease liabilities, net of current portion ​ $ 16,567 ​ $ 20,421 Finance lease liabilities ​ Finance lease liabilities, net of current portion ​ ​ 51 ​ ​ 10 Total non-current lease liabilities ​ ​ ​ ​ 16,618 ​ ​ 20,431 Total lease liabilities ​ ​ ​ $ 20,409 ​ $ 24,620 ​ ​ The major components of lease cost are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2023 ​ 2022 ​ 2021 ​ ​ ​ ​ ​ ​ Operating lease cost $ 4,019 ​ $ 3,714 ​ $ 4,774 ​ ​ ​ ​ ​ ​ ​ ​ ​ Finance lease cost: ​ ​ ​ ​ ​ ​ ​ ​ Amortization of lease assets ​ 788 ​ ​ 1,275 ​ ​ 931 Interest on lease liabilities ​ 8 ​ ​ 18 ​ ​ 16 Total lease cost $ 4,815 ​ $ 5,007 ​ $ 5,721 ​ ​ The weighted-average term and discount rate for leases are as follows: ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ ​ 2023 ​ 2022 ​ Weighted-average remaining lease term (years): ​ ​ ​ ​ Operating leases 4.7 ​ 5.7 ​ Finance leases 2.1 ​ 0.5 ​ ​ ​ ​ ​ ​ Weighted-average discount rate: ​ ​ ​ ​ Operating leases 2.3 % 2.3 % Finance leases 5.6 % 2.3 % ​ ​ Lease liability maturities for the next five years and thereafter are as follows as of December 31, 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating Leases Finance Leases ​ 2024 ​ $ 4,228 ​ $ 75 ​ 2025 ​ ​ 4,493 ​ ​ 45 ​ 2026 ​ ​ 4,565 ​ ​ 11 ​ 2027 ​ ​ 4,636 ​ ​ — ​ 2028 ​ ​ 3,494 ​ ​ — ​ Thereafter ​ ​ — ​ ​ — ​ Total lease payments ​ ​ 21,416 ​ ​ 131 ​ Less: Imputed interest ​ ​ (1,132) ​ ​ (6) ​ Present value of lease liabilities ​ $ 20,284 ​ $ 125 ​ ​

GOODWILL AND OTHER INTANGIBLE A

GOODWILL AND OTHER INTANGIBLE ASSETS	12 Months Ended
	Dec. 31, 2023
GOODWILL AND OTHER INTANGIBLE ASSETS
GOODWILL AND OTHER INTANGIBLE ASSETS	9. Goodwill and other intangible assets are as follows for the periods presented: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ ​ 2023 ​ 2022 Goodwill ​ $ 257,842 ​ $ 251,842 Other intangible assets, net ​ ​ 2,396 ​ 5,181 Total ​ $ 260,238 ​ $ 257,023 ​ ​ ​ ​ ​ ​ ​ ​ The changes in the carrying amount of goodwill are as follows for the periods presented: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ ​ 2023 ​ 2022 Balance, January 1 ​ $ 251,842 ​ $ 270,041 Measurement period adjustments ​ ​ — ​ ​ (10,329) Foreign currency translation adjustments ​ ​ 6,000 ​ ​ (7,870) Balance, December 31, gross ​ ​ 257,842 ​ ​ 251,842 Accumulated impairment losses ​ ​ — ​ ​ — Balance, December 31, net ​ $ 257,842 ​ $ 251,842 ​ The Company recognized various amortizable other intangible assets in connection with acquisitions, including customer relationships, technology, and tradenames. The following tables provide additional information for our other intangible assets, which are individually not material to the consolidated financial statements: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ ​ ​ ​ ​ ​ ​ ​ 2023 ​ 2022 Weighted average amortization period (years) ​ ​ ​ ​ ​ 3.5 ​ ​ 3.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2023 ​ ​ As of December 31, 2022 ​ ​ ​ Gross Carrying Amount ​ ​ Accumulated Amortization ​ ​ Gross Carrying Amount ​ ​ Accumulated Amortization Customer relationships ​ $ 8,348 ​ $ 6,385 ​ $ 8,225 ​ $ 3,855 Trademarks and tradenames ​ ​ 1,303 ​ ​ 1,119 ​ ​ 1,240 ​ ​ 887 Developed technology ​ ​ 1,309 ​ ​ 1,060 ​ ​ 1,202 ​ ​ 744 Total ​ $ 10,960 ​ $ 8,564 ​ $ 10,667 ​ $ 5,486 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ ​ Cost of Revenues, Software Subscriptions ​ Selling and Marketing Expense ​ ​ Total Expense 2023 ​ ​ ​ $ 243 $ 2,641 ​ $ 2,884 2022 ​ ​ ​ ​ ​ 234 ​ ​ 3,779 ​ ​ 4,013 2021 ​ ​ ​ ​ ​ 253 ​ ​ 813 ​ ​ 1,066 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The following table presents estimated future amortization of intangible assets over their remaining estimated useful lives: ​ ​ ​ ​ ​ Year Ending December 31, ​ 2024 ​ $ 2,110 2025 ​ 286 Total ​ $ 2,396 ​ ​ The Company recorded other intangible assets of $6,500 during the year ended December 31, 2022 in connection with finalization of the LCR-Dixon acquisition opening balance sheet. The Company recorded amortization expense of $2,825 for the year ended December 31, 2022, which is included in cost of revenues, software subscriptions, and selling and

DEBT

DEBT	12 Months Ended
	Dec. 31, 2023
DEBT
DEBT	10. DEBT Credit Agreement On March 31, 2020, the Company entered into a credit agreement (“the Previous Credit Agreement”) with a bank consisting of a $175,000 term loan (the “Previous Term Loan”) and a $100,000 committed line of credit (the “Previous Line of Credit”). On March 8, 2022, the Company entered into the Second Amendment to Credit Agreement (the “Second Amendment”), with a banking syndicate, which amended the Previous Credit Agreement, providing for, among other modifications, (i) a new term loan in the aggregate amount of $50,000 (the “Term Loan”); (ii) an extension of the maturity date of the revolving facility (“the Line of Credit”) from March 2025 to March 2027; (iii) an increase in the Line of Credit commitment from $100,000 to $200,000 (iv) the Company’s option to select an applicable interest rate at either the bank base rate plus an applicable margin (the “New Base Rate Option”) or Secured Overnight Financing Rate (“SOFR”) plus an applicable margin (the “SOFR Option”); (v) modifications to the financial covenant performance levels which determine applicable margins; and (vi) modifications to certain covenants and events of default. Net proceeds from the Term Loan were used to fund ongoing working capital, capital expenditures, permitted distributions, permitted acquisitions, and general corporate purposes of the Company and its subsidiaries. The Company paid $983 in financing costs in connection with the Second Amendment, which are being amortized over the term of the loan. The Company wrote off $370 in deferred financing fees pertaining to the Previous Credit Agreement associated with a bank exiting the Second Amendment. The remaining balance of deferred financing costs of $277, pertaining to the remaining bank associated with the Previous Credit Agreement are being amortized over the term of the Second Amendment. The portion of the deferred financing costs associated with the Line of Credit and the Term Loan are reflected in other assets and as a reduction of the Term Loan, respectively, in the consolidated balance sheets at December 31, 2023 and 2022. On December 12, 2023, the Company entered into the Third Amendment to Credit Agreement (the “Third Amendment” collectively, with the Previous Credit Agreement and the Second Amendment, the “Credit Agreement”), with the existing banking syndicate, which provided funding for a proposed acquisition. On December 13, 2023, the Company announced that it had commenced a public tender offer to acquire a global provider of e-invoicing solutions. The Company intended to fund the transaction with proceeds from the Line of Credit and from the issuance of a new series of convertible preferred equity (“Convertible Preferred Equity”). On January 14, 2024, the Company withdrew its public tender offer. See Note 3 for more information on the public tender offer. Certain provisions under the Third Amendment, including the ability to issue the Convertible Preferred Equity, will expire on April 30, 2024. The majority of the provisions provided by the Third Amendment were contingent upon the completion of the acquisition and the issuance of the Convertible Preferred Equity, which will no longer occur, and therefore, immediately revert to the terms of the Second Amendment. ​ The Company incurred $1,112 Outstanding borrowings under the Credit Agreement are collateralized by nearly all of the assets of the Company and contain financial and operating covenants. The Company was in compliance with these covenants at December 31, 2023 and 2022. The Credit Agreement also limits the declaration or payment of certain dividends not to exceed an aggregate of $2,000. Term Loan The Term Loan requires quarterly principal payments over five years, with a balloon payment due on March 8, 2027. The interest rate on the Term Loan was 6.46% and 5.42% at December 31, 2023 and 2022, respectively, as the Company selected the SOFR Option. Term Loan outstanding amounts are reported in the current portion of long-term debt and long-term debt, net of current portion, in the consolidated balance sheets. Outstanding borrowings under the Term Loan were $46,875 and $49,063 at December 31, 2023 and 2022, respectively. Line of Credit The Line of Credit expires in March 2027. The Company is required to pay a quarterly fee on the difference between the $200,000 allowed maximum borrowings and the unpaid principal balance outstanding under the line at the applicable rate. At December 31, 2023, the New Base Rate Option and SOFR Option applicable to the Line of Credit borrowings were 8.50% and 6.48%, respectively. There were no outstanding borrowings under the Line of Credit at December 31, 2023 or 2022. Our indebtedness at December 31, 2023 and December 31, 2022 was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ ​ 2023 ​ ​ 2022 Term Loan $ 2,500 ​ $ 2,188 Current portion of long-term debt ​ 2,500 ​ ​ 2,188 ​ ​ ​ ​ ​ ​ Term Loan ​ 44,375 ​ ​ 46,875 Deferred financing costs ​ (316) ​ ​ (166) Debt, net of current portion $ 44,059 ​ $ 46,709 Total debt $ 46,559 ​ $ 48,897 ​ Debt maturities under the Credit Agreement for the next five years and thereafter are as follows as of December 31, 2023: ​ ​ ​ ​ ​ Year Ending December 31, ​ ​ ​ 2024 ​ $ 2,500 2025 ​ ​ 2,500 2026 ​ ​ 3,437 2027 ​ ​ 38,438 Total debt, net of financing costs ​ $ 46,875 ​

STOCKHOLDERS' EQUITY

STOCKHOLDERS' EQUITY	12 Months Ended
	Dec. 31, 2023
STOCKHOLDERS' EQUITY
STOCKHOLDERS' EQUITY	11. Common Stock During 2023, the Company issued 2,468 shares of Class A common stock (“Class A”) related to the exercise of options, net of 314 shares returned to the Company in lieu of payment of the exercise price and taxes due on these exercises. The Company issued 511 shares of Class A in 2023 in connection with the vesting of RSUs, net of 285 shares returned to the Company in lieu of payment of taxes due on the vesting of these awards. The Company issued 198 shares of Class A in 2023 in connection with the vesting of RSAs, net of 7 shares returned to the Company in lieu of payment of taxes due on the vesting of these awards. The Company also issued 152 shares in connection with the ESPP Plan in 2023. During 2023, stockholders exchanged 7,646 shares of Class B common stock (“Class B”) for an equivalent number of shares of Class A. During 2022, the Company issued 800 shares of Class A related to the exercise of options, net of 91 shares returned to the Company in lieu of payment of the exercise price and taxes due on these exercises. The Company issued 48 shares of Class A in 2022 in connection with the vesting of RSUs, net of 20 shares returned to the Company in lieu of payment of taxes due on the vesting of these awards. The Company issued 173 shares of Class A in 2022 in connection with the vesting of RSAs, net of 15 shares returned to the Company in lieu of payment of taxes due on the vesting of these awards. The Company also issued 207 shares in connection with the ESPP Plan in 2022. During 2022, stockholders exchanged 6,500 shares of Class B for an equivalent number of shares of Class A. During 2021, the Company issued 2,157 shares of Class A related to the exercise of options, net of 706 shares returned to the Company in lieu of payment of the exercise price and taxes due on these exercises. The Company issued 12 shares of Class A in 2021 in connection with the vesting of RSUs net of 3 shares returned to the Company in lieu of payment of taxes due on the vesting of these awards. The Company issued 352 shares of Class A in 2021 in connection with the vesting of RSAs, net of 11 shares returned to the Company in lieu of payment of taxes due on the vesting of these awards. The Company also issued 128 shares in connection with the ESPP Plan in 2021. During 2021, a stockholder exchanged 13,310 shares of Class B for an equivalent number of shares of Class A. Tax Sharing Agreement Payments In connection with revocation of the Company’s S-Corporation election effective July 27, 2020, the Company entered into a Tax Sharing Agreement with the former S-Corporation shareholders. See Note 1. All obligations of the Company under the Tax Sharing Agreement are satisfied by adjustments of additional paid in capital. No payments were required under the Tax Sharing Agreement in 2023. On March 15, 2022, the Company distributed $536 to the former S-Corporation shareholders under the Tax Sharing Agreement to settle the Company’s obligation for income taxes related to the allocation of taxable income to the S-Corporation short tax period ended July 26, 2020. Through the year ended December 31, 2021, the Company distributed $2,733 to the former S-Corporation shareholders under the Tax Sharing Agreement.

EARNINGS PER SHARE

EARNINGS PER SHARE	12 Months Ended
	Dec. 31, 2023
EARNINGS PER SHARE
EARNINGS PER SHARE	12 . The tables below illustrate the calculation of basic and diluted net loss per common share for the Class A and Class B for the periods reflected below. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ Class A common stock: 2023 ​ 2022 ​ 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Numerator, basic: ​ ​ ​ ​ ​ Net loss attributable to all stockholders $ (13,093) ​ $ (12,304) ​ $ (1,479) ​ Class A common stock as a percentage of total shares outstanding, basic 36.06 % 30.65 % 24.12 % Net loss attributable to Class A stockholders, basic $ (4,721) ​ $ (3,771) ​ $ (357) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Numerator, diluted: ​ ​ ​ ​ ​ Net loss attributable to all stockholders $ (13,093) ​ $ (12,304) ​ $ (1,479) ​ Class A common stock as a percentage of total shares outstanding, diluted 36.06 % 30.65 % 24.12 % Net loss attributable to Class A stockholders, diluted $ (4,721) ​ $ (3,771) ​ $ (357) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Denominator, basic and diluted: ​ ​ ​ Weighted average Class A common stock, basic 54,753 ​ 45,864 ​ 35,647 ​ Dilutive effect of common stock equivalents (1) (2) (3) — ​ — ​ — ​ Weighted average Class A common stock, diluted 54,753 ​ 45,864 ​ 35,647 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net loss per Class A share, basic $ (0.09) ​ $ (0.08) ​ $ (0.01) ​ Net loss per Class A share, diluted $ (0.09) ​ $ (0.08) ​ $ (0.01) ​ 1) . ​ 2) . ​ 3) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ Class B common stock: 2023 ​ 2022 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Numerator, basic: ​ ​ ​ Net loss attributable to all stockholders $ (13,093) ​ $ (12,304) ​ $ (1,479) ​ Class B common stock as a percentage of total shares outstanding, basic 63.94 % 69.35 % 75.88 % Net loss attributable to Class B stockholders, basic $ (8,372) ​ $ (8,533) ​ $ (1,122) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Numerator, diluted: ​ ​ ​ Net loss attributable to all stockholders $ (13,093) ​ $ (12,304) ​ $ (1,479) ​ Class B common stock as a percentage of total shares outstanding, diluted 63.94 % 69.35 % 75.88 % Net loss attributable to Class B stockholders, diluted $ (8,372) ​ $ (8,533) ​ $ (1,122) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Denominator, basic and diluted: ​ ​ ​ Weighted average Class B common stock, basic 97,106 ​ 103,781 ​ 112,133 ​ Dilutive effect of common stock equivalents — ​ — ​ — ​ Weighted average Class B common stock, diluted 97,106 ​ 103,781 ​ 112,133 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net loss per Class B share, basic $ (0.09) ​ $ (0.08) ​ $ (0.01) ​ Net loss per Class B share, diluted $ (0.09) ​ $ (0.08) ​ $ (0.01) ​ ​

EMPLOYEE BENEFIT AND DEFERRED C

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS	12 Months Ended
	Dec. 31, 2023
EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS
EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS	13 . The Company maintains a 401(k) plan that covers eligible employees. For the year ended December 31, 2021, the Company matched up to to 3% of eligible compensation during the period in which an eligible participant contributed to the plan and the Board approved a discretionary profit-sharing contribution of 3% of eligible compensation for eligible employees. Discretionary profit-sharing contributions aggregated $3,994 for the year ended December 31, 2021. Effective January 1, 2022, discretionary profit-sharing contributions were eliminated and the Company began to match up to 6% of eligible compensation during the period in which an eligible participant contributes to the plan. Matching 401(k) contributions were $11,285, $10,056, and $4,062 for the years ended December 31, 2023, 2022, and 2021, respectively. Long-Term Rewards Plan The Company had a long-term reward (“LTR”) compensation plan for certain key employees related to growth in certain financial measures over a three-year measurement period (the “Reward Performance Period’), subject to the terms of the plan. After December 31, 2020, no new awards were granted under the LTR plan as future long-term awards will only be made under the 2020 Plan. Eligible LTR plan participants received an individual target award opportunity for a new three-year Reward Performance Period (i.e., target award grant made in 2019 is for years 2019 through 2021). Compensation earned for growth in the financial measures over each Reward Performance Period is paid in cash in the year following the end of the respective Reward Performance Period, assuming the minimum net income target was achieved in the final year of the Reward Performance Period. Estimated compensation is recorded during each year of a Reward Performance Period. At December 31, 2022, the Company had one open Reward Performance Period, which was paid in 2023. Compensation expense associated with LTR plan was $0, $892, and $3,059 for the years ended December 31, 2023, 2022, and 2021, respectively. Amounts paid in 2023 and 2022 for the LTR plan were $2,237 and $4,023, respectively. Stock-Based Award Plans The 2020 Plan provides the ability to grant cash and equity-based incentive awards to eligible employees, directors and service providers in order to attract, retain, and motivate those that make important contributions to the Company. The 2020 Plan provides for the award of stock options, RSAs, RSUs, and other cash compensation. The ESPP provides eligible employees with rights during each six-month ESPP offering period to purchase shares of the Company’s Class A at the ESPP discount through payroll deductions. Amounts withheld or received from participants are reflected in accrued salaries and benefits in the consolidated balance sheets until such shares are purchased. Amounts withheld from participants for the offering periods ending May 31, 2024 and 2023 aggregated $371 and $311 as of December 31, 2023 and 2022, respectively. 2020 Plan Upon commencement of the 2020 Plan, an aggregate of 16,500 shares of our Class A were available for issuance. The number of shares available for issuance are increased annually on January 1 of each calendar year beginning in 2021 and ending in and including 2030, equal to the lesser of (i) 4% of the shares of Class A and Class B outstanding on the final day of the immediately preceding calendar year and (ii) a smaller number of shares as determined by the Board. No more than 3,000 shares of Class A may be issued under the 2020 Plan upon the exercise of incentive stock options. Shares available under the 2020 Plan may consist of authorized but unissued shares, shares purchased on the open market, or treasury shares. If an award under the 2020 Plan expires, lapses, or is terminated, exchanged for cash, surrendered, repurchased, or canceled without having been fully exercised or forfeited, any unused shares subject to the award will again be available for new grants under the 2020 Plan. Awards granted under the 2020 Plan in substitution for any options or other stock or stock-based awards granted by an entity before the entity’s merger or consolidation with or acquisition by the Company of the entity’s property or stock will not reduce the shares available for grant under the 2020 Plan but will count against the maximum number of shares that may be issued upon the exercise of incentive stock options. As of December 31, 2023, 15,676 shares of our Class A were available for issuance under the 2020 Plan. No incentive stock options that would be subject to the 3,000 Class A share limit were issued or outstanding under the 2020 Plan at December 31, 2023. Awards issued under the 2020 Plan vest based on service criteria established by the Board. The Company has elected to account for forfeitures as they occur rather than estimate forfeitures at date of grant. ​ ​ ​ ​ Options under 2020 Plan The following table summarizes activity for options outstanding under the 2020 Plan: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ Average ​ ​ ​ ​ ​ ​ ​ Average ​ Remaining ​ Aggregate ​ ​ ​ ​ ​ Exercise ​ Contractual ​ Intrinsic 2020 Plan Option Activity ​ Units ​ ​ Price ​ Life (Years) ​ Value Outstanding at January 1, 2023 ​ 8,508 ​ $ 4.34 ​ 4.3 ​ $ 86,514 Exercised ​ (2,782) ​ $ 2.32 ​ ​ ​ ​ ​ Forfeited ​ (34) ​ $ 5.82 ​ ​ ​ ​ ​ 2020 Plan options outstanding at December 31, 2023 ​ 5,692 ​ $ 5.32 ​ 4.7 ​ ​ 124,327 2020 Plan options exercisable at December 31, 2023 4,289 ​ $ 4.31 4.1 ​ ​ 97,737 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The detail of options outstanding, vested and exercisable under the 2020 Plan as of December 31, 2023 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Options Outstanding ​ Options Vested and Exercisable ​ ​ Weighted ​ Weighted ​ ​ ​ ​ Average ​ ​ ​ Average Exercise Prices ​ Units ​ Life (Years) ​ Units ​ Life (Years) $0.15 to $0.71 786 ​ * ​ 786 ​ * $2.15 147 ​ 1.1 ​ 147 ​ 1.1 $2.50 1,721 ​ 2.7 ​ 1,721 ​ 2.7 $2.67 63 ​ 3.1 ​ 63 ​ 3.1 $3.17 431 ​ 4.4 ​ 431 ​ 4.4 $3.73 ​ 1,236 ​ 5.8 ​ 490 ​ 5.8 $4.70 ​ 603 ​ 6.1 ​ 261 ​ 6.1 $18.47 ​ 213 ​ 7.9 ​ 107 ​ 7.9 $18.96 ​ 185 ​ 7.6 ​ 120 ​ 7.6 $19.00 65 ​ 7.7 ​ 32 ​ 7.7 $32.16 242 ​ 7.2 ​ 131 ​ 7.2 ​ ​ 5,692 ​ ​ 4,289 ​ ​ *These Options have indefinite contractual lives. ​ ​ ​ ​ ​ ​ ​ ​ The Board intends all options granted to be exercisable at a price per share not less than the per share fair market value of the Company’s Class A underlying the options on the date of grant. Compensation expense to participants under the 2020 Plan is measured based on the grant date fair value of the awards and recognized in the consolidated statements of comprehensive loss over the period during which the participant is required to perform the requisite services. The vesting period is generally one The Company issued 779 options under the 2020 Plan in 2021. No options were issued during 2022 or 2023. The assumptions used in the Black-Scholes models to determine the value of the options issued during these periods are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Option Valuation Period ​ ​ Q4 2021 Q3 2021 ​ Q3 2021 Q2 2021 Q1 2021 Fair market value of common stock $ 18.47 ​ $ 18.96 ​ ​ $ 19.00 ​ $ 17.66 ​ $ 32.16 ​ Volatility 37.4 % 37.1 % ​ 37.1 % 36.8 % 36.8 % Expected term (years) 5.0 ​ ​ 5.0 ​ ​ 5.0 ​ ​ 6.0 ​ ​ 6.0 ​ Expected dividend yield — % ​ — % ​ — % ​ — % ​ — % Risk-free interest rate 1.3 % ​ 0.8 % ​ 0.9 % ​ 0.4 % ​ 0.4 % ​ The fair market value of common stock reflects the market closing price on the NASDAQ Global Market exchange on the respective option grant date. As of the valuation dates, the Company lacked sufficient historical data on the volatility of its stock price. Selected volatility is representative of expected future volatility and was based on the historical and implied volatility of comparable publicly traded companies over a similar expected term. The expected term represents the term the options are expected to be exercised over, which differs from the term of the option grants which is ten years. The Company does not expect to pay dividends. The risk-free interest rate was based on the rate for a U.S. Treasury zero-coupon issue with a term that closely approximates the expected term of the option grants. At December 31, 2023, $4,756 of unrecognized compensation expense associated with the options is expected to be recognized over a weighted average period of approximately 1.2 years. Restricted Stock Units The following table summarizes RSU activity for the periods presented: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ ​ ​ Grant Date Fair ​ ​ Units ​ Value Per Share Outstanding at January 1, 2023 ​ 2,562 ​ $ 15.90 Granted ​ 2,627 ​ ​ 16.64 Vested ​ (796) ​ ​ 17.45 Forfeited ​ (222) ​ ​ 15.23 Outstanding at December 31, 2023 ​ 4,171 ​ $ 16.11 ​ Stock-based compensation cost for RSUs is measured based on the fair value of the Company’s underlying common stock on the date of grant. Compensation cost will be recognized on a straight-line basis in the consolidated statements of comprehensive loss over the period during which the participant is required to perform services in exchange for the award, which is generally one In connection with the Taxamo acquisition, certain continuing employees of Taxamo received RSUs with service and performance conditions, which were measured as of December 31, 2023. These targets were not met, therefore, no compensation expense was recorded and they have been forfeited as of December 31, 2023. Restricted Stock Awards The following table summarizes RSA activity for the periods presented: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ ​ ​ Grant Date Fair ​ ​ Units ​ Value Per Share Outstanding at January 1, 2023 ​ 235 ​ $ 14.91 Granted 62 ​ ​ 22.69 Vested (206) ​ 14.32 Outstanding at December 31, 2023 91 ​ $ 21.50 ​ Stock-based compensation cost for RSAs is measured based on the fair value of the Company’s underlying common stock on the date of grant. Compensation cost will be recognized on a straight-line basis in the consolidated statements of comprehensive loss over the period during which the participants are required to perform services in exchange for the award, which is generally one Employee Stock Purchase Plan The ESPP permits participants to purchase Class A primarily through payroll deductions of up to a specified percentage of their eligible compensation. The maximum number of shares that may be purchased by a participant during any offering period is determined by the plan administrator in advance of each offering period. A total of 1,000 shares of Class A were initially reserved for issuance under the ESPP. The number of shares available for issuance under the ESPP increases annually on January 1 of each calendar year beginning in 2021 and ending in and including 2030, by an amount equal to the lesser of (i) 1% of the shares of Class A and Class B outstanding on the final day of the immediately preceding calendar year and (ii) such smaller number of shares as is determined by the Board, provided that no more than 16,000 shares of Class A may be issued. The ESPP is administered by a committee of the Board. As of December 31, 2023, there were 4,914 shares available for issuance under the ESPP. On the first trading day of each offering period, each participant will automatically be granted an option to purchase shares of Class A. The option will expire at the end of the applicable offering period and will be exercised at that time to the extent of the payroll deductions accumulated or contributions made during such offering period. The purchase price of the shares, in the absence of a contrary designation, is 85% of the lower of the fair value of the Class A on the first or last day of the ESPP offering period. Participants may voluntarily end their participation in the plan at any time during a specified period prior to the end of the applicable offering period and will be paid their accrued payroll deductions and related contributions, if applicable, that have not yet been used to purchase shares of Class A. If a participant withdraws from the plan during an offering period, the participant cannot rejoin until the next offering period. Participation ends automatically upon a participant's termination of employment. As of December 31, 2023 and 2022, there was approximately $375 and $324, respectively, of unrecognized ESPP stock-based compensation cost that is expected to be recognized on a straight-line basis over the remaining term of the offering periods ending on May 31, 2024 and 2023, respectively. The fair value of ESPP purchase rights for the offering periods is comprised of the value of the 15% ESPP discount and the value associated with the call or put over the respective ESPP offering period. ESPP offering periods reflected in the December 31, 2023, financial statements include the periods noted below in the table. The value of the call or put was estimated using the Black-Scholes model with the following assumptions: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Offering Period Ending ​ 5/31/2024 ​ 11/30/2023 ​ 5/31/2023 ​ 11/30/2022 ​ 5/31/2022 ​ Fair market value of common stock $ 27.82 ​ $ 21.76 ​ $ 17.21 ​ $ 11.16 ​ $ 17.38 ​ Volatility 36.6 % 39.4 % 46.4 % 35.4 % 37.3 % Expected term (years) 0.5 ​ 0.5 ​ 0.5 ​ 0.5 ​ 0.5 ​ Expected dividend yield - % - % - % - % - % Risk-free interest rate 5.3 % 5.4 % 4.7 % 1.6 % 0.1 % ​ Volatility is representative of expected stock price volatility over the offering period. Effective with the offering period beginning December 1, 2022, the Company’s volatility was applied and will be applied to future offering periods. Prior to this offering period, volatility was based on the historical and implied volatility of comparable publicly traded companies over a similar expected term for the respective offering periods. The expected term represents the term of the ESPP offering period, which is six months. The risk-free interest rate was based on the rate for a U.S. Treasury zero-coupon issue with a term that closely approximates the expected term of the award at the date nearest the offering term. ​ Stock-Based Compensation The Company recognized total stock-based compensation cost related to incentive awards, net of forfeitures, as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2023 2022 2021 Stock-based compensation expense: ​ ​ ​ ​ ​ ​ ​ ​ ​ Stock options ​ $ 6,349 ​ $ 7,081 ​ $ 17,533 RSUs ​ 24,257 ​ 9,286 ​ 2,964 RSAs ​ 2,496 ​ 2,768 ​ 5,126 ESPP ​ ​ 817 ​ ​ 594 ​ ​ 537 Total stock-based compensation expense ​ $ 33,919 ​ $ 19,729 ​ $ 26,160 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The Company recognized stock-based compensation cost in the consolidated statements of comprehensive loss as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2023 2022 2021 Stock-based compensation expense: ​ ​ ​ ​ ​ ​ ​ ​ Cost of revenues, software subscriptions $ 2,834 ​ $ 2,090 $ 2,336 Cost of revenues, services 1,846 ​ 1,433 2,648 Research and development 5,994 ​ 1,798 2,620 Selling and marketing 8,380 ​ 6,284 6,371 General and administrative 14,865 ​ 8,124 ​ ​ 12,185 Total stock-based compensation expense $ 33,919 ​ $ 19,729 ​ $ 26,160 ​ The total recognized tax benefit related to the stock-based compensation expense for the years ended December 31, 2023, 2022, and 2021 was $16,541, $3,324, and $14,683, respectively. The tax benefit from stock options exercised during the years ended December 31, 2023, 2022, and 2021 was $13,079, $2,710, and $14,159, respectively.

RELATED PARTIES

RELATED PARTIES	12 Months Ended
	Dec. 31, 2023
RELATED PARTIES
RELATED PARTIES	14. In connection with the termination of the Company’s S-corporation status and our establishment of a new capital structure, which both occurred in July 2020, the Company entered into the Third Amended and Restated Stockholders' Agreement (the “Stockholders’ Agreement”) with the Class B shareholders. The Stockholders’ Agreement entitles these individuals to require the Company to register shares held by them for sale (the “Selling Shareholder Registrations”). The Stockholders’ Agreement requires the Company to pay the expenses relating to Selling Shareholder Registrations and to indemnify the parties participating in these offerings against liabilities that may arise from the offering process. No offering costs related to the sale of shares associated with the Selling Shareholder Registration were incurred during the year ended December 31, 2023. For the year ended December 31, 2022, the Company incurred $688 in offering costs related to the sale of shares associated with the Selling Shareholder Registration.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2023
COMMITMENTS AND CONTINGENCIES
COMMITMENTS AND CONTINGENCIES	15. In January 2022, the Company filed a complaint against a competitor alleging claims of unfair competition, intentional interference with contractual relations, and trade secret misappropriation. The outcome of the case is subject to a number of uncertainties, therefore the Company has not recognized any potential impact to the consolidated financial statements. The Company may become involved in various lawsuits and legal proceedings, which arise, in the ordinary course of business. However, litigation is subject to inherent uncertainties, and an adverse result in these or other matters may arise from time to time that may harm the Company’s business. The Company is not aware of any such legal proceedings or claims that management believes will have a material adverse effect on its business, financial condition, or operating results. Purchase Obligations In the ordinary course of business, the Company enters into non-cancelable agreements with third-party providers, primarily for subscriptions and the use of cloud services. Future minimum payments as of December 31, 2023 are summarized in the table below: ​ ​ ​ ​ 2024 $ 10,450 2025 ​ 7,452 2026 ​ 4,568 2027 ​ 3,696 2028 ​ 3,075 ​ $ 29,241 ​ ​

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2023
INCOME TAXES
INCOME TAXES	16. INCOME TAXES The components of net loss before income taxes, by geography, are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2023 2022 2021 U.S. ​ $ (3,126) ​ $ 5,827 ​ $ 5,608 Foreign ​ (18,548) ​ (15,957) ​ (9,534) Net loss before income taxes ​ $ (21,674) ​ $ (10,130) ​ $ (3,926) ​ Income tax expense (benefit) consists of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2023 2022 2021 Current income taxes: ​ ​ ​ Federal ​ $ (279) ​ $ 1,696 ​ $ — State and local ​ ​ 1,568 ​ ​ 1,068 ​ ​ 155 Foreign ​ 1,347 ​ 577 ​ 468 Total current ​ 2,636 ​ 3,341 ​ 623 Deferred income taxes: ​ ​ ​ Federal ​ ​ (9,224) ​ ​ 904 ​ ​ (1,849) State and local ​ (1,552) ​ 72 ​ (7) Foreign ​ (441) ​ (2,143) ​ (1,214) Total deferred ​ (11,217) ​ (1,167) ​ (3,070) Income tax expense (benefit) ​ $ (8,581) ​ $ 2,174 ​ $ (2,447) ​ During the year ended December 31, 2023, the Company recognized a $27 income tax expense in accumulated other comprehensive loss relating to unrealized gains (losses) from foreign currency translation adjustments, revaluations, and available-for-sale securities. During the year ended December 31, 2022, the Company recognized a $12 income tax benefit in accumulated other comprehensive loss relating to unrealized gains from foreign currency translation adjustments and revaluations, and available-for-sale securities. The reconciliation of the effective tax rate to tax at the statutory rates for the years ended December 31 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2023 2022 2021 ​ ​ Total ​ Tax Rate ​ Total ​ Tax Rate Total ​ Tax Rate Pretax net loss ​ $ (21,674) ​ $ (10,130) ​ $ (3,926) ​ Taxes: ​ ​ ​ ​ ​ ​ U.S. federal income tax at statutory rate ​ $ (4,552) 21.0 % $ (2,128) 21.0 % $ (825) 21.0 % State income taxes ​ ​ 289 (1.3) % ​ 441 (4.4) % ​ 678 (17.3) % Stock-based compensation expense ​ ​ (6,236) ​ 28.8 % ​ 1,787 ​ (17.6) % ​ (4,550) ​ 115.9 % Impact of foreign operations ​ 1,463 ​ (6.8) % 1,352 ​ (13.3) % 954 ​ (24.3) % Transaction costs ​ ​ — ​ 0.0 % ​ 176 ​ (1.7) % ​ 1,082 ​ (27.6) % U.S. taxation of foreign earnings ​ ​ (245) ​ 1.1 % ​ (179) ​ 1.8 % ​ 144 ​ (3.7) % Nondeductible compensation ​ ​ 2,822 ​ (13.0) % ​ 485 ​ (4.8) % ​ 682 ​ (17.4) % Tax credits ​ ​ (5,818) ​ 26.8 % ​ (341) ​ 3.4 % ​ (488) ​ 12.4 % Change in valuation allowance ​ ​ 3,386 ​ (15.6) % ​ 427 ​ (4.2) % ​ 373 ​ (9.5) % Changes in prior year unrecognized tax benefits ​ ​ 451 ​ (2.1) % ​ — ​ 0.0 % ​ — ​ 0.0 % Other permanent items, net ​ ​ (141) 0.7 % ​ 154 (1.7) % ​ (497) 12.8 % Taxes and effective tax rate ​ $ (8,581) 39.6 % $ 2,174 (21.5) % $ (2,447) 62.3 % ​ The effective tax rate in 2023 increased to 39.6% from (21.5)% in 2022. The increase in income tax benefit in 2023 was primarily driven by changes in tax benefits on exercises and vestings of stock awards, tax credits, valuation allowances on net deferred tax assets established for certain foreign jurisdictions, loss before income tax, and limitations on deductions of certain employees’ compensation under Internal Revenue Code (“IRC”) Section 162(m). ​ The effective tax rate in 2022 decreased to (21.5)% from 62.3% in 2021. The income tax expense in 2022 was primarily driven by a net shortfall in tax benefits on exercises and vestings of stock awards and limitations on deductions of certain employees’ compensation under IRC Section 162(m), partially offset by the favorable impact of tax credits and foreign tax benefits from the deduction for foreign-derived intangible income. The impact of foreign operations in 2023, 2022, and 2021 primarily reflects losses in Ireland taxed at 12.5%, as well as income or losses taxed at rates in other foreign jurisdictions, as opposed to the statutory U.S. federal income tax rate. Significant components of the Company’s net deferred tax assets (liabilities) are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, Deferred tax assets: 2023 2022 Deferred revenue ​ $ 3,523 ​ $ 2,981 State operating loss carry forwards ​ 2,682 ​ 2,831 Federal and foreign loss carry forwards ​ 4,361 ​ 11,318 Accrued expenses ​ 2,239 ​ 2,238 Accrued compensation ​ 2,339 ​ — Deferred and stock-based compensation ​ 19,008 ​ 23,634 Operating lease liabilities ​ ​ 5,151 ​ ​ 6,272 Tax credits ​ ​ 3,662 ​ ​ — Depreciation and amortization ​ ​ 6,417 ​ ​ — Other ​ 2,721 ​ — Deferred tax assets ​ 52,103 ​ 49,274 Valuation allowance ​ (5,941) ​ (2,285) Total deferred tax assets ​ 46,162 ​ 46,989 Deferred tax liabilities: ​ ​ Depreciation and amortization ​ — ​ (9,337) Prepaid expenses ​ ​ (1,026) ​ ​ (1,256) Right of use asset ​ (3,428) ​ (4,325) Accrued compensation ​ ​ — ​ ​ (1,434) Other ​ ​ — ​ ​ (115) Total deferred tax liabilities ​ (4,454) ​ (16,467) Net deferred tax asset ​ $ 41,708 ​ $ 30,522 ​ ​ ​ ​ ​ ​ ​ Classification in the consolidated balance sheets: ​ ​ ​ ​ ​ ​ Deferred income tax asset ​ $ 41,708 ​ $ 30,938 Deferred other liabilities ​ ​ — ​ ​ (416) Net deferred tax asset ​ $ 41,708 ​ $ 30,522 ​ At December 31, 2023, the Company has no U.S. federal operating loss carry forwards and available U.S. state operating loss carry forwards of $42,090. The state operating losses will expire at varying dates beginning in 2031 through 2043 or will carry forward indefinitely. Management expects to fully use these U.S. state operating loss carry forwards. At December 31, 2023, the Company has available foreign operating losses of approximately $27,577 and nontrading losses of $51, which generally carry forward indefinitely. A valuation allowance for a portion of the foreign operating and non-operating losses is recorded at December 31, 2023 and 2022. At December 31, 2023, the Company has available U.S. federal R&D tax credit carryovers of $4,014. The credits will expire from 2041 through 2043. Management expects to fully use these U.S. federal credit carry forwards. At December 31, 2023 and 2022, the Company has a valuation allowance of ($5,941) and ($2,285), respectively, primarily against certain net deferred tax assets, including losses, in foreign jurisdictions. The net increase in the total valuation allowance of ($3,656) during December 31, 2023 primarily related to recording additional valuation allowance on net deferred tax assets in foreign jurisdictions that, in the judgment of management, are not more likely than not to be realized, partially offset by the release of a valuation allowance on the net deferred tax asset in foreign jurisdictions, which management believes is more likely than not to be realized, as well as changes in foreign exchange rates. The does not assert any earnings to be permanently reinvested with respect to the undistributed earnings of its foreign subsidiaries. The Company files tax returns as prescribed by the tax laws of the jurisdictions in which the Company operates. Under applicable U.S. federal statutes, tax years ended December 31, 2020 through December 31, 2023 remain subject to examination. Under applicable statutes, state and foreign corporate tax returns filed for the Company and its respective foreign subsidiaries for years ended December 31, 2018 through December 31, 2023 remain subject to examination by the respective authorities.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2023
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Nature of Business	Nature of Business Vertex, Inc. (“Vertex”) and its consolidated subsidiaries and variable interest entities (“VIE”) (collectively, the “Company”) operate as solutions providers of state, local and value added tax calculation, compliance, and analytics, offering software products which are sold through software license and software as a service (“cloud”) subscriptions. The Company also provides implementation and training services in connection with its software license and cloud subscriptions, transaction tax returns outsourcing, and other tax-related services. The Company sells to customers located throughout the United States of America (“U.S.”) and internationally.
Basis of Consolidation	Basis of Consolidation The consolidated financial statements are prepared in accordance with accounting principles generally accepted in the U.S. (“U.S. GAAP”) and include the accounts of the Company. All intercompany transactions have been eliminated in consolidation. The Company had an 80% and 65% controlling equity interest in Systax Sistemas Fiscais LTDA (“Systax”), a provider of Brazilian transaction tax content and software at December 31, 2023 and 2022, respectively. Systax was determined to be a VIE and the accounts are included in the consolidated financial statements. Vertex does not have full decision-making authority over Systax; however, Vertex is the entity that most significantly participates in the variability of the fair value of Systax’s net assets and is considered the entity most closely associated to Systax. As such, Vertex is deemed the primary beneficiary of Systax and consolidates Systax into its consolidated financial statements.
Revision of Previously Issued Financial Statements	Revision of Previously Issued Financial Statements ​ Certain prior period amounts on the consolidated balance sheets and consolidated statements of cash flows, reflected in the tables below, have been revised to correct for certain immaterial errors, as described below. During the second quarter of 2023, management identified certain immaterial errors impacting previously issued financial statements beginning as of December 31, 2021, and subsequent annual and quarterly reporting periods through March 31, 2023. Specifically, management identified an error in financial statement presentation required to be corrected to correctly reflect Cloud Computing Arrangement (“CCA”) software implementation costs in accordance with Accounting Standards Codification (“ASC”) 350-40, Goodwill and Other, Internal-Use Software Management assessed the materiality of this presentation on prior period consolidated financial statements in accordance with the Securities and Exchange Commission (“SEC”) Staff Accounting Bulletin No. 99, “Materiality,” codified in ASC 250, Accounting Changes and Error Corrections ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The consolidated balance sheets have been revised to reflect the correction as follows : ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 ​ As Reported ​ ​ Revision ​ ​ As Revised Property and equipment, net of accumulated depreciation $ 98,390 ​ $ (1,680) ​ $ 96,710 Other assets ​ 1,900 ​ ​ 1,680 ​ ​ 3,580 ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2022 (unaudited) ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment, net of accumulated depreciation $ 102,228 ​ $ (4,642) ​ $ 97,586 Other assets ​ 3,158 ​ ​ 4,642 ​ ​ 7,800 ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, 2022 (unaudited) ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment, net of accumulated depreciation $ 106,526 ​ $ (7,668) ​ $ 98,858 Other assets ​ 2,592 ​ ​ 7,668 ​ ​ 10,260 ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2022 (unaudited) ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment, net of accumulated depreciation $ 109,123 ​ $ (11,107) ​ $ 98,016 Other assets ​ 2,422 ​ ​ 11,107 ​ ​ 13,529 ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 ​ ​ ​ ​ ​ ​ ​ ​ Prepaid expenses and other current assets $ 20,383 ​ $ 1,957 ​ $ 22,340 Total current assets ​ 241,189 ​ ​ 1,957 ​ ​ 243,146 Property and equipment, net of accumulated depreciation ​ 115,768 ​ ​ (14,678) ​ ​ 101,090 Other assets ​ 2,612 ​ ​ 12,721 ​ ​ 15,333 ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2023 (unaudited) ​ ​ ​ ​ ​ ​ ​ ​ Prepaid expenses and other current assets $ 22,536 ​ $ 3,588 ​ $ 26,124 Total current assets ​ 231,435 ​ ​ 3,588 ​ ​ 235,023 Property and equipment, net of accumulated depreciation ​ 117,444 ​ ​ (17,942) ​ ​ 99,502 Other assets ​ 2,621 ​ ​ 14,354 ​ ​ 16,975 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The effect on the consolidated statements of cash flows are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Twelve months ended December 31, 2021 ​ ​ As Reported ​ ​ Revision ​ ​ As Revised Cash flows from operating activities: ​ ​ ​ ​ ​ ​ ​ ​ Other changes in operating assets and liabilities $ 336 ​ $ (1,680) ​ $ (1,344) Net cash (used in) provided by operating activities ​ 91,969 ​ ​ (1,680) ​ ​ 90,289 ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from investing activities: ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment additions ​ (33,386) ​ ​ 1,680 ​ ​ (31,706) Net cash used in investing activities ​ (296,458) ​ ​ 1,680 ​ ​ (294,778) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended March 31, 2022 (unaudited) ​ As Reported ​ ​ Revision ​ ​ As Revised Cash flows from operating activities: ​ ​ ​ ​ ​ ​ ​ ​ Other changes in operating assets and liabilities $ (950) ​ $ (2,962) ​ $ (3,912) Net cash (used in) provided by operating activities ​ 2,595 ​ ​ (2,962) ​ ​ (367) ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from investing activities: ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment additions ​ (13,873) ​ ​ 2,962 ​ ​ (10,911) Net cash used in investing activities ​ (17,259) ​ ​ 2,962 ​ ​ (14,297) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Six months ended June 30, 2022 (unaudited) ​ As Reported ​ ​ Revision ​ ​ As Revised Cash flows from operating activities: ​ ​ ​ ​ ​ ​ ​ ​ Other changes in operating assets and liabilities $ (457) ​ $ (5,988) ​ $ (6,445) Net cash (used in) provided by operating activities ​ 14,576 ​ ​ (5,988) ​ ​ 8,588 ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from investing activities: ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment additions ​ (27,827) ​ ​ 5,988 ​ ​ (21,839) Net cash used in investing activities ​ (41,170) ​ ​ 5,988 ​ ​ (35,182) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine months ended September 30, 2022 (unaudited) ​ As Reported ​ ​ Revision ​ ​ As Revised Cash flows from operating activities: ​ ​ ​ ​ ​ ​ ​ ​ Other changes in operating assets and liabilities $ (349) ​ $ (9,427) ​ $ (9,776) Net cash (used in) provided by operating activities ​ 33,026 ​ ​ (9,427) ​ ​ 23,599 ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from investing activities: ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment additions ​ (42,973) ​ ​ 9,427 ​ ​ (33,546) Net cash used in investing activities ​ (59,862) ​ ​ 9,427 ​ ​ (50,435) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Twelve months ended December 31, 2022 ​ ​ As Reported ​ ​ Revision ​ ​ As Revised Cash flows from operating activities: ​ ​ ​ ​ ​ ​ ​ ​ Prepaid expenses and other current assets $ (214) ​ $ (1,957) ​ $ (2,171) Other changes in operating assets and liabilities ​ (583) ​ ​ (11,041) ​ ​ (11,624) Net cash (used in) provided by operating activities ​ 76,846 ​ ​ (12,998) ​ ​ 63,848 ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from investing activities: ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment additions ​ (58,530) ​ ​ 12,998 ​ ​ (45,532) Net cash used in investing activities ​ (85,046) ​ ​ 12,998 ​ ​ (72,048) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended March 31, 2023 (unaudited) ​ As Reported ​ ​ Revision ​ ​ As Revised Cash flows from operating activities: ​ ​ ​ ​ ​ ​ ​ ​ Prepaid expenses and other current assets $ (2,109) ​ $ (1,631) ​ $ (3,740) Other changes in operating assets and liabilities ​ (58) ​ ​ (1,633) ​ ​ (1,691) Net cash (used in) provided by operating activities ​ 6,755 ​ ​ (3,264) ​ ​ 3,491 ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from investing activities: ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment additions ​ (13,313) ​ ​ 3,264 ​ ​ (10,049) Net cash used in investing activities ​ (17,561) ​ ​ 3,264 ​ ​ (14,297) ​ The consolidated balance sheet as of December 31, 2022 and the consolidated statements of cash flows for the years ended December 31, 2022 and 2021 have been revised in this Annual Report on Form 10-K. The Company intends to revise the remaining quarterly and annual amounts affected in future filings in which they appear, as applicable.
Segments	Segments The Company operates its business as one operating segment. Operating segments are defined as components of an enterprise about which separate financial information is evaluated regularly by the chief operating decision maker (“CODM”), the Company’s Chief Executive Officer, in deciding how to allocate resources and assess performance. The Company’s CODM allocates resources and assesses performance based upon discrete financial information at the consolidated level. For the years ended December 31, 2023, 2022, and 2021 approximately 8%, 8%, and 7%, respectively, of the Company’s revenues were generated outside of the U.S. As of December 31, 2023 and 2022, $633 and $827 respectively, of the Company’s property and equipment assets were held outside of the U.S.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject the Company to credit risk consist principally of cash and cash equivalents, which includes highly liquid investment securities, available-for-sale securities, funds held for customers and accounts receivable. The Company maintains the majority of its cash and cash equivalent balances and funds held for customers in four banks. These amounts exceed federally insured (“FDIC”) limits. The Company periodically evaluates the creditworthiness of the banks. The Company has not experienced any losses in these accounts and believes they are not exposed to significant credit risk on such accounts. The Company does not require collateral from its customers. Allowances are maintained for credit losses. Credit risk related to accounts receivable is limited due to the industry and geographic diversity within the Company's customer base. No single customer accounted for more than 10% of revenues for the years ended December 31, 2023, 2022, and 2021.
Fair Value Measurement	Fair Value Measurement Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at a measurement date. A three-level fair value hierarchy (the “Fair Value Hierarchy”) prioritizes the inputs used to measure fair value. The Fair Value Hierarchy requires the Company to maximize the use of observable inputs and minimize the use of unobservable inputs. Classification in the Fair Value Hierarchy is based on the lowest of the following levels that is significant to the measurement: Level 1 Level 2 Level 3 The Company’s assessment of the significance of an input to a fair value measurement requires judgment, which may affect the determination of fair value and the measurement’s classification within the Fair Value Hierarchy.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, equity, revenues, and expenses during the reporting period. Significant estimates used in preparing these consolidated financial statements include: (i) the estimated allowance for subscription cancellations; (ii) expected credit losses associated with the allowance for doubtful accounts; (iii) allowance for credit losses on available-for-sale debt securities; (iv) the reserve for self-insurance; (v) assumptions related to achievement of technological feasibility for software developed for sale; (vi) product life cycles; (vii) estimated useful lives and potential impairment of long-lived assets, intangible assets, and capitalized CCA software implementation costs; (viii) potential impairment of goodwill; (ix) determination of the fair value of tangible and intangible assets acquired, liabilities assumed, and consideration transferred in acquisitions; (x) amortization period of material rights and deferred commissions; (xi) Black-Scholes-Merton option pricing model (“Black-Scholes model”) input assumptions used to determine the fair value of certain stock-based compensation awards and Employee Stock Purchase Plan (“ESPP”) purchase rights; (xii) measurement of future purchase commitment, contingent consideration liabilities, and deferred purchase consideration liabilities associated with acquisitions; and (xiii) the potential outcome of future tax consequences of events that have been recognized in the consolidated financial statements or tax returns. Actual results may differ from these estimates.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments purchased with an initial maturity date of three months or less to be cash equivalents. Funds held as investments in money market funds are included within cash and cash equivalents. In accordance with Accounting Standards Update (“ASU”) No. 2016-18, Restricted Cash
Funds Held for Customers	Funds Held for Customers Funds held for customers in the consolidated balance sheets represents customer funds advanced for transaction tax returns outsourcing. Funds held for customers are restricted for the sole purpose of remitting such funds to satisfy obligations on behalf of such customers and are deposited at FDIC-insured institutions. Customer obligations are included in current liabilities in the consolidated balance sheets, as the obligations are expected to be settled within one year.
Property and Equipment	Property and Equipment Property and equipment are stated at cost or fair value when acquired and presented net of accumulated depreciation. Normal maintenance and repairs are charged to expense, while major renewals and betterments are capitalized. Assets under finance leases are recorded at the present value of future lease payments. Assets under capital leases are recorded at the lower of the present value of the minimum lease payments or the fair value of the assets and are depreciated over the shorter of the asset’s useful life or lease term. ​ ​ Depreciation and amortization are computed straight-line over the estimated useful lives of the assets, as follows: ​ ​ ​ ​ Leasehold improvements 1 - 12 years Internal-use software developed 3 - 5 years Computer software purchased 3 - 7 years Equipment 3 - 10 years Furniture and fixtures 7 - 10 years ​
Software Development Costs	Software Development Costs Cloud Computing Software Implementation Costs ​ The Company follows ASC 350-40 to account for development costs incurred for cloud computing software implementations. ASC 350-40 requires such costs to be capitalized once certain criteria are met. Costs are primarily comprised of contracted labor, direct labor, and related expenses. ASC 350-40 includes specific guidance on costs not to be capitalized, such as overhead, general and administrative, and training costs. Costs are capitalized once the project is defined, funding is committed, and it is confirmed the software will be used for its intended use. Capitalization of these costs concludes once the project is substantially complete and the software is ready for its intended purpose. Post-configuration training and maintenance costs are expensed as incurred. ​ two ​ Amortization expense for capitalized cloud computing implementation costs for the year ended December 31, 2023 was $2,570 and is included in general and administrative expense in the consolidated statements of comprehensive loss. There was no amortization expense for the years ended December 31, 2022 or 2021.
Internal-Use Software	Internal-Use Software The Company follows ASC 350-40 to account for development costs incurred for the costs of computer software developed or obtained for internal use. ASC 350-40 requires such costs to be capitalized once certain criteria are met. Capitalized internal-use software costs are primarily comprised of direct and contracted labor, and related expenses. ASC 350-40 includes specific guidance on costs not to be capitalized, such as overhead, general and administrative, and training costs. Internal-use software includes software utilized for cloud-based solutions as well as software for internal systems and tools. Costs are capitalized once the project is defined, funding is committed, and it is confirmed the software will be used for its intended use. Capitalization of these costs concludes once the project is substantially complete and the software is ready for its intended purpose. Post-configuration training and maintenance costs are expensed as incurred. Internal-use software is included in internal-use software developed in property and equipment in the consolidated balance sheets once available for its intended use. Depreciation expense for internal-use software utilized for cloud-based customer solutions and for software for internal systems and tools is included in cost of revenues, software subscriptions, and depreciation and amortization, respectively, in the consolidated statements of comprehensive loss.
Software Developed for Sale	Software Developed for Sale The costs incurred for the development of computer software to be sold, leased, or otherwise marketed are capitalized in accordance with ASC 985-20, Costs of Software to be Sold, Leased or Marketed Amortization of capitalized software development costs begins when the product is available for general release. Amortization is provided on a product-by-product basis using the straight-line method over periods between three Capitalized software costs are subject to an ongoing assessment of recoverability based on anticipated future revenues and changes in software technologies at each balance sheet date. In the event of impairment, unamortized capitalized software costs are compared to the net realizable value of the related product and the carrying value of the related assets are written down to the net realizable value to the extent the unamortized capitalized costs exceed such value. The net realizable value is the estimated future gross revenues from the related product reduced by the estimated future costs of completing and disposing of such product, including the costs of providing related maintenance and customer support.
Assessment of Long-Lived Assets	Assessment of Long-Lived Assets The Company reviews the carrying value of long-lived assets, including internal-use software, for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be fully recoverable. Whenever such events or circumstances are present, an impairment loss equal to the excess of the asset carrying value over its fair value, if any, is recorded.
Business Combinations	Business Combinations Upon acquisition of a company, the Company determines if the transaction is a business combination, which is accounted for using the acquisition method of accounting. Under the acquisition method, once control is obtained of a business, the assets acquired, liabilities assumed, consideration transferred and amounts attributed to noncontrolling interests, are recorded at fair value. The Company uses its best estimates and assumptions to assign fair value to the tangible and intangible assets acquired, liabilities assumed, consideration transferred, and amounts attributed to noncontrolling interests at the acquisition date. One of the most significant estimates relates to the determination of the fair value of these amounts. The determination of the fair values is based on estimates and judgments made by management. The Company’s estimates of fair value are based upon assumptions it believes to be reasonable, but which are inherently uncertain and unpredictable. Measurement period adjustments to these values as of the acquisition date are reflected at the time identified, up through the conclusion of the measurement period, which is the time at which all information for determination of the values of assets acquired, liabilities assumed, consideration transferred, and noncontrolling interests is received, and is not to exceed one year from the acquisition date (the “Measurement Period”). Thus, the Company may record adjustments to the fair value of these tangible and intangible assets acquired, liabilities assumed, consideration transferred, and noncontrolling interests, with the corresponding offset to goodwill during this Measurement Period. Additionally, uncertain tax positions and tax-related valuation allowances are initially recorded in connection with a business combination as of the acquisition date. The Company continues to collect information and reevaluate these estimates and assumptions periodically and record any adjustments to preliminary estimates to goodwill, provided the Company is within the Measurement Period, with any adjustments to amortization of new or previously recorded identifiable intangibles being recorded to the consolidated statements of comprehensive loss in the period in which they arise. In addition, if outside of the Measurement Period, any subsequent adjustments to the acquisition date fair values are reflected in the consolidated statements of comprehensive loss in the period in which they arise.
Goodwill	Goodwill Goodwill represents the excess of the purchase price over the fair value of net tangible and intangible assets acquired in a business combination. The Company evaluates goodwill for impairment annually at October 1 and whenever events or circumstances make it more likely than not that impairment may have occurred. The Company has determined that its business comprises one reporting unit. The Company has the option to first assess qualitative factors to determine whether events or circumstances indicate it is more likely than not that the fair value of a reporting unit is greater than its carrying amount, in which case a quantitative impairment test is not required. As provided for by ASU 2017-04, Simplifying the Test for Goodwill Impairment
Deferred Financing Costs	Deferred Financing Costs The Company capitalizes costs related to obtaining, renewing, or extending loan agreements and amortizes these costs on a straight-line basis, which approximates the effective interest method, over the life of the loan. Deferred financing costs related to undrawn debt are reflected in other assets in the consolidated balance sheets in accordance with ASC 835-30, Interest—Imputation of Interest
Stock-Based Compensation	Stock-Based Compensation The 2020 Incentive Award Plan (the “2020 Plan”) and the ESPP provide for the award of stock appreciation rights (“SARs”), stock options (“options”), restricted stock awards (“RSAs”), restricted stock units (“RSUs”), and participation in the ESPP (collectively, the “awards”). The awards are subject to, and the Company applies, the guidance set forth in ASC 718, Compensation—Stock Compensation The provisions of ASC 718 require a company to measure the fair value of stock-based compensation as of the grant date of the award. Stock-based compensation expense reflects the cost of employee services received in exchange for the awards. Stock-based compensation expense for stock options issued under the 2020 Plan is measured based on the grant date fair value of the award and is estimated using the Black-Scholes model. Compensation cost is recognized on a straight-line basis over the requisite service or performance period associated with the award. Stock-based compensation expense for RSAs and RSUs is based on the fair value of the Company’s underlying common stock on the date of grant. Compensation cost is recognized on a straight-line basis over the requisite service or performance period associated with the award. Stock-based compensation expense for awards subject to performance-based measurement criteria is recognized when achievement of performance targets is deemed probable. The ESPP permits participants to purchase Class A common stock through payroll deductions, up to a specified percentage of their eligible compensation. The plan is a compensatory plan as it allows participants to purchase stock at a 15% discount from the lower of the fair value of the Class A common on the first or last day of the ESPP offering period (the “ESPP Discount”). The ESPP is accounted for as an equity classified award. Stock-based compensation expense for the ESPP is measured based on the fair value of the ESPP award at the start of the offering period. The fair value is comprised of the value of the ESPP Discount and the value associated with the variability in the Class A common stock price during the offering period (the “Call/Put”), which is estimated using the Black-Scholes model. Compensation cost is recognized on a straight-line basis over the respective offering period. The Company has elected to recognize award forfeitures as they occur.
Leases	Leases In accordance with ASU No. 2016-02, Leases For leases with terms greater than 12 months, the Company records an operating lease right-of-use asset or finance lease asset and related lease liability at the present value of lease payments over the lease term. The implicit rate for individual leases is generally not readily determinable; therefore, the Company uses its incremental borrowing rate at lease commencement to determine the present value of lease payments. Leases with an option to extend the related lease term or terminate early are reflected in the lease term when it is reasonably certain that the Company will exercise such options. The Company recognizes expense for operating leases on a straight-line basis over the lease term plus any variable lease costs. The Company does not recognize a right-of-use asset or lease liability for leases with an initial term equal to or less than 12 months (“short-term leases”) on its consolidated balance sheets. The Company recognizes expense on short-term leases in the consolidated statements of comprehensive loss on a straight-line basis over the lease term.
Self-insurance	Self-insurance The Company is self-insured for the majority of its health insurance costs, including medical claims subject to certain stop-loss provisions. Management periodically reviews the adequacy of the Company’s stop-loss insurance coverage. The Company records an estimate of claims incurred but not reported, based on management’s judgment and historical experience. Self-insurance accruals are $2,246 and $2,219 at December 31, 2023 and 2022, respectively, and are reflected in accrued salaries and benefits in the consolidated balance sheets. Material differences may result in the amount and timing of insurance expense if actual experience differs significantly from management’s estimates.
Revenue Recognition	Revenue Recognition Revenue from contracts with customers The Company recognizes revenue in accordance with ASC 606, Revenue from Contracts with Customers Nature of goods and services Licenses for on-premise software subscriptions, which are generally one year, provide the customer with a right to use the software as it exists when made available to the customer. Customers purchase a subscription to these licenses, which includes the related software and tax content updates and product support. The updates and support, which are part of the subscription agreement, are essential to the continued utility of the software; therefore, the Company has determined the software and the related updates and support to be a single performance obligation. Accordingly, when on-premise software is licensed, the revenue associated with this combined performance obligation is recognized ratably over the license term as these subscriptions are provided for the duration of the license term. Revenue recognition begins on the later of the beginning of the subscription period or the date the software is made available to the customer to download. Prior to January 1, 2022, certain on-premise software subscription prices in the initial subscription year were higher than standard renewal prices. The excess initial year price over the renewal price is a material right that provides customers with the right to this reduced renewal price. The Company recognizes revenue associated with this material right over the estimated period of benefit to the customer, which is generally three years. Effective January 1, 2022, the Company changed the pricing structure for on-premise software so the initial year price and renewal prices were consistent, thus removing the material right for transactions after this date. The material right for applicable transactions prior to this pricing change will continue to be recognized over the remaining estimated period of benefit to the customer. Cloud-based subscriptions allow customers to use Company-hosted software over the contract period without taking possession of the software. The cloud-based offerings also include related updates and support. Revenue recognition begins on the later of the beginning of the subscription period or the date the customer is provided access to the cloud-based solutions. Cloud-based contracts consistently provide a benefit to the customer during the subscription period; thus, the associated revenue is recognized ratably over the related subscription period. Revenue from deliverable-based services is recognized as services are delivered. Revenue from fixed fee services is recognized as services are performed using the percentage of completion input method. The Company has elected the “right to invoice” practical expedient for revenue related to services that are billed on an hourly basis, which enables revenue to be recognized as the services are performed. The Company has determined that the methods applied to measuring its progress toward complete satisfaction of performance obligations recognized over time are a faithful depiction of the transfer of control of software subscriptions and services to customers. Significant Judgments Contracts with customers often include promises to transfer multiple products and services to a customer. Determining whether products and services are considered distinct performance obligations that should be accounted for separately versus together may require significant judgment. Identification of the amortization periods of material rights and contract costs requires significant judgment by management. Payment Terms Payment terms and conditions vary by contract, although the Company’s terms generally include a requirement of payment within 30-60 days. In instances where the timing of revenue recognition differs from the timing of payment, the Company has determined that its contracts do not include a significant financing component. The primary purpose of invoicing terms is to provide customers with simplified and predictable ways of purchasing products and services, not to receive financing from customers or to provide customers with financing. Cost of Revenues Cost of revenues, software subscriptions include the direct cost to develop, host, and distribute software products, the direct cost to provide customer support, and amortization of costs capitalized for software developed for sale, for internal-use software utilized for cloud-based subscriptions and for certain acquired intangible assets. Cost of revenues, services include the direct costs of implementation, training, transaction tax returns outsourcing, and other tax-related services. Reimbursable Costs Reimbursable costs passed through and invoiced to customers of the Company are recorded as services revenues with the associated expenses recorded as cost of revenues, services in the consolidated statements of comprehensive loss. These amounts were $17, $133, and $14 for the years ended December 31, 2023, 2022, and 2021, respectively.
Research and Development	Research and Development Research and development costs consist primarily of personnel and related expenses for research and development activities including salaries, benefits, and other compensation. Research and development costs are expensed as incurred in accordance with ASC 730, Research and Development,
Advertising	Advertising Advertising expense is recorded as incurred and is reflected in selling and marketing expense in the consolidated statements of comprehensive loss. Total advertising expense was $26,000, $26,529, and $20,386 for the years ended December 31, 2023, 2022, and 2021, respectively.
Foreign Currency	Foreign Currency The Company transacts business in various foreign currencies. Management has concluded that the local country’s currency is the functional currency of its foreign operations. Consequently, operating activities outside the U.S. are translated into U.S. dollars using average exchange rates, while assets and liabilities of operations outside the U.S. are translated into U.S. dollars using exchange rates at the balance sheet date. The effects of foreign currency translation adjustments are included in total stockholders’ equity as a component of accumulated other comprehensive loss in the consolidated balance sheets. Related periodic movements in exchange rates are included in other comprehensive income loss in the consolidated statements of comprehensive loss. Other operating expense, net in the consolidated statements of comprehensive loss includes net foreign exchange transaction (losses) gains of $(109), $(38), and $183 for the years ended December 31, 2023, 2022, and 2021, respectively.
Investments	Investments The Company’s investment securities portfolio consists of the following: money market mutual funds invested in high quality, short-term money market instruments which are issued and payable in U.S. dollars (“Money Market Funds”), bank and corporate issued commercial paper (“Commercial Paper”), and U.S. treasury securities (“Treasury Securities”). The Money Market Funds and a portion of the Commercial Paper are considered cash and cash equivalents due to their short maturity dates. These securities are carried at fair value, with the realized holding gains and (losses), net of tax, reported in the interest expense, net line of the consolidated statements of comprehensive loss. Realized holding gains and (losses), net of tax, were not material. The Money Market Funds qualify as equity securities per ASC 321, Investments – Equity Securities Investments– Debt Securities
Income Taxes	Income Taxes The Company accounts for income taxes using the asset and liability method, which recognizes deferred tax assets and liabilities for future tax consequences of events that have been previously recognized in the Company’s consolidated financial statements or tax returns. The measurement of deferred tax assets and liabilities is based on provisions of the enacted tax law and rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect of a change in tax laws or rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. The effects of future changes in tax laws or rates are not anticipated. A valuation allowance is recorded when it is more likely than not that some or all of the deferred tax assets will not be realized. The Company records uncertain tax positions in accordance with ASC 740, Income Taxes The impact as a result of the application of ASC 740 is reflected in the consolidated financial statements. The Company assesses its income tax positions and records tax benefits or expense based upon management’s evaluation of the facts, circumstances, and information available at the reporting date. Variations in the actual outcome of these future tax consequences could materially impact the consolidated financial statements. Effective July 27, 2020, Vertex is taxed as a C-Corporation for U.S federal and state income tax purposes upon revocation of the Company’s S-Corporation election (the “S Election”) in connection with the initial public offering, that closed on July 28, 2020. In foreign jurisdictions, Vertex subsidiaries are generally taxed at the corporate level, and the income tax provision or benefit is based on income or loss sourced to these foreign jurisdictions at the tax rates applicable in those jurisdictions. In connection with revocation of the Company’s S-Corporation election, which became effective July 27, 2020, the Company entered into an agreement with the S-Corporation stockholders pursuant to which the Company indemnified them for unpaid income tax liabilities and may be required to make future payments in material amounts to them attributable to incremental income taxes resulting from an adjustment to S-Corporation related taxable income that arises after the effective date of the S Election revocation (the “Tax Sharing Agreement”). In addition, the Tax Sharing Agreement indemnifies the S-Corporation stockholders for any interest, penalties, losses, costs, or expenses arising out of any claim under the agreement. Correspondingly, the S-Corporation stockholders indemnified the Company with respect to unpaid tax liabilities (including interest and penalties) to the extent that such unpaid tax liabilities are attributable to a decrease in S-Corporation stockholders’ taxable income for any period and a corresponding increase in our taxable income for any period.
Total Comprehensive Income (Loss)	Total Comprehensive Income (Loss) Total comprehensive income (loss) consists of net income (loss) and other comprehensive income (loss). Other comprehensive income (loss) refers to revenues, expenses, gains and losses that under U.S. GAAP are recorded as elements of stockholders' equity but are excluded from net income (loss). Other comprehensive income (loss) is comprised of foreign currency translation adjustments and revaluations, and unrealized gains (losses) on available-for-sale debt securities.
Earnings Per Share ("EPS")	Earnings Per Share (“EPS”) The Company has two classes of common stock outstanding and thus calculates EPS following the two-class method. This method allocates earnings for the respective periods between the two classes of common stock in proportion to the weighted average shares outstanding for each class of common stock as a percentage of total weighted average shares of both classes of common stock outstanding. Neither the Class A nor Class B common stock has any liquidity or dividend preferences and are both considered to be participating securities. Basic and diluted net income (loss) per share attributable to common stockholders is calculated using the treasury stock method. The basic net income (loss) per share attributable to Class A common stockholders includes RSAs, RSUs, and ESPP shares once vesting or purchase contingencies are resolved, and the related shares are deemed to be outstanding. The diluted net income (loss) per share attributable to Class A common stockholders is computed by giving effect to all potential dilutive common stock equivalents outstanding for the period. For purposes of this calculation, all options to purchase shares of Class A common stock and nonvested RSAs and RSUs are considered common stock equivalents. Additionally, the portion of ESPP shares for which the Company has received payments but for which the related shares are not yet issuable are also considered potential common stock equivalents. In periods of net loss available to common stockholders, diluted calculations are equal to basic calculations because the inclusion of potential common stock equivalents would be anti-dilutive.
Supplemental Balance Sheet Information	Supplemental Balance Sheet Information Supplemental balance sheet disclosures are as follows for the respective periods: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ 2023 ​ 2022 Prepaid expenses and other current assets: ​ ​ Prepaid expenses ​ $ 11,558 ​ $ 5,875 Unamortized cloud computing implementation costs ​ ​ 3,995 ​ ​ 1,957 Prepaid insurance ​ ​ 521 ​ ​ 2,291 Prepaid licenses and support ​ ​ 10,099 ​ ​ 12,217 Prepaid expenses and other current assets ​ $ 26,173 ​ $ 22,340 ​ ​ ​ ​ ​ ​ ​ Other assets: ​ ​ ​ ​ Unamortized cloud computing implementation costs ​ $ 12,475 ​ $ 12,721 Other assets ​ ​ 3,538 ​ ​ 2,612 Total other assets ​ $ 16,013 ​ $ 15,333 ​ ​ ​ ​ ​ ​ ​ Accrued expenses: ​ ​ ​ ​ ​ ​ Accrued general expenses ​ $ 25,998 ​ $ 18,485 Accrued contract labor and professional fees ​ ​ 13,372 ​ ​ 17,421 Accrued income and other taxes ​ ​ 5,365 ​ ​ 2,328 Accrued expenses ​ $ 44,735 ​ $ 38,234 ​ ​ ​ ​ ​ ​ ​
Supplemental Cash Flow Disclosures	Supplemental Cash Flow Disclosures Supplemental cash flow disclosures are as follows for the respective periods: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2023 2022 ​ 2021 Cash paid for: ​ ​ ​ ​ Interest ​ $ 3,729 ​ $ 2,221 ​ $ 223 Income taxes, net of refunds ​ ​ 5,652 ​ ​ 3,059 ​ ​ 1,287 Cash paid included in the measurement of lease liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating cash flows from operating leases ​ ​ 4,019 ​ ​ 4,240 ​ ​ 4,692 Non-cash investing and financing activities: ​ ​ ​ ​ ​ ​ ​ Change in settlement value of deferred purchase commitment liability ​ ​ 4,020 ​ ​ 990 ​ ​ — Change in fair value of contingent consideration liability ​ ​ 1,549 ​ ​ 2,300 ​ ​ 300 Estimated distributions payable under Tax Sharing Agreement ​ ​ — ​ ​ — ​ ​ 536 Purchase commitment and contingent consideration liabilities ​ ​ — ​ ​ — ​ ​ 12,736 Deferred purchase consideration ​ ​ — ​ ​ — ​ ​ 39,024 Leased assets obtained in exchange for new finance lease liabilities ​ ​ 124 ​ ​ 1,069 ​ ​ 173
Recently Issued or Adopted Accounting Pronouncements	Recently Issued Or Adopted Accounting Pronouncements Prior to December 31, 2023, the Company qualified as an “emerging growth company,” under the Jumpstart Our Business Startups Act (the “JOBS Act”), which allowed the Company to delay the adoption of new or revised accounting pronouncements applicable to public companies, until such pronouncements were made applicable to private companies. The Company may have previously elected to delay adoption of certain new or revised accounting standards. As a result, the Company’s consolidated financial statements may not have been comparable to the financial statements of issuers who are required to comply with the effective date for new or revised accounting standards that are applicable to public companies. Disclosure Improvements Disclosure Update and Simplification Segment Reporting In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures Income Tax Disclosures In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740):Improvements to Income Tax Disclosures. continuing to assess the potential impacts of the standard, and it does not expect this pronouncement to have a material effect on its financial statements, other than the required changes to the income tax disclosures.

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
	Dec. 31, 2023
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Schedule of property plant and equipment useful life	​ ​ ​ ​ Leasehold improvements 1 - 12 years Internal-use software developed 3 - 5 years Computer software purchased 3 - 7 years Equipment 3 - 10 years Furniture and fixtures 7 - 10 years ​
Schedule of revision of previously issued financial statements	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The consolidated balance sheets have been revised to reflect the correction as follows : ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 ​ As Reported ​ ​ Revision ​ ​ As Revised Property and equipment, net of accumulated depreciation $ 98,390 ​ $ (1,680) ​ $ 96,710 Other assets ​ 1,900 ​ ​ 1,680 ​ ​ 3,580 ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2022 (unaudited) ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment, net of accumulated depreciation $ 102,228 ​ $ (4,642) ​ $ 97,586 Other assets ​ 3,158 ​ ​ 4,642 ​ ​ 7,800 ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, 2022 (unaudited) ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment, net of accumulated depreciation $ 106,526 ​ $ (7,668) ​ $ 98,858 Other assets ​ 2,592 ​ ​ 7,668 ​ ​ 10,260 ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2022 (unaudited) ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment, net of accumulated depreciation $ 109,123 ​ $ (11,107) ​ $ 98,016 Other assets ​ 2,422 ​ ​ 11,107 ​ ​ 13,529 ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 ​ ​ ​ ​ ​ ​ ​ ​ Prepaid expenses and other current assets $ 20,383 ​ $ 1,957 ​ $ 22,340 Total current assets ​ 241,189 ​ ​ 1,957 ​ ​ 243,146 Property and equipment, net of accumulated depreciation ​ 115,768 ​ ​ (14,678) ​ ​ 101,090 Other assets ​ 2,612 ​ ​ 12,721 ​ ​ 15,333 ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2023 (unaudited) ​ ​ ​ ​ ​ ​ ​ ​ Prepaid expenses and other current assets $ 22,536 ​ $ 3,588 ​ $ 26,124 Total current assets ​ 231,435 ​ ​ 3,588 ​ ​ 235,023 Property and equipment, net of accumulated depreciation ​ 117,444 ​ ​ (17,942) ​ ​ 99,502 Other assets ​ 2,621 ​ ​ 14,354 ​ ​ 16,975 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The effect on the consolidated statements of cash flows are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Twelve months ended December 31, 2021 ​ ​ As Reported ​ ​ Revision ​ ​ As Revised Cash flows from operating activities: ​ ​ ​ ​ ​ ​ ​ ​ Other changes in operating assets and liabilities $ 336 ​ $ (1,680) ​ $ (1,344) Net cash (used in) provided by operating activities ​ 91,969 ​ ​ (1,680) ​ ​ 90,289 ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from investing activities: ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment additions ​ (33,386) ​ ​ 1,680 ​ ​ (31,706) Net cash used in investing activities ​ (296,458) ​ ​ 1,680 ​ ​ (294,778) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended March 31, 2022 (unaudited) ​ As Reported ​ ​ Revision ​ ​ As Revised Cash flows from operating activities: ​ ​ ​ ​ ​ ​ ​ ​ Other changes in operating assets and liabilities $ (950) ​ $ (2,962) ​ $ (3,912) Net cash (used in) provided by operating activities ​ 2,595 ​ ​ (2,962) ​ ​ (367) ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from investing activities: ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment additions ​ (13,873) ​ ​ 2,962 ​ ​ (10,911) Net cash used in investing activities ​ (17,259) ​ ​ 2,962 ​ ​ (14,297) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Six months ended June 30, 2022 (unaudited) ​ As Reported ​ ​ Revision ​ ​ As Revised Cash flows from operating activities: ​ ​ ​ ​ ​ ​ ​ ​ Other changes in operating assets and liabilities $ (457) ​ $ (5,988) ​ $ (6,445) Net cash (used in) provided by operating activities ​ 14,576 ​ ​ (5,988) ​ ​ 8,588 ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from investing activities: ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment additions ​ (27,827) ​ ​ 5,988 ​ ​ (21,839) Net cash used in investing activities ​ (41,170) ​ ​ 5,988 ​ ​ (35,182) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine months ended September 30, 2022 (unaudited) ​ As Reported ​ ​ Revision ​ ​ As Revised Cash flows from operating activities: ​ ​ ​ ​ ​ ​ ​ ​ Other changes in operating assets and liabilities $ (349) ​ $ (9,427) ​ $ (9,776) Net cash (used in) provided by operating activities ​ 33,026 ​ ​ (9,427) ​ ​ 23,599 ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from investing activities: ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment additions ​ (42,973) ​ ​ 9,427 ​ ​ (33,546) Net cash used in investing activities ​ (59,862) ​ ​ 9,427 ​ ​ (50,435) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Twelve months ended December 31, 2022 ​ ​ As Reported ​ ​ Revision ​ ​ As Revised Cash flows from operating activities: ​ ​ ​ ​ ​ ​ ​ ​ Prepaid expenses and other current assets $ (214) ​ $ (1,957) ​ $ (2,171) Other changes in operating assets and liabilities ​ (583) ​ ​ (11,041) ​ ​ (11,624) Net cash (used in) provided by operating activities ​ 76,846 ​ ​ (12,998) ​ ​ 63,848 ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from investing activities: ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment additions ​ (58,530) ​ ​ 12,998 ​ ​ (45,532) Net cash used in investing activities ​ (85,046) ​ ​ 12,998 ​ ​ (72,048) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended March 31, 2023 (unaudited) ​ As Reported ​ ​ Revision ​ ​ As Revised Cash flows from operating activities: ​ ​ ​ ​ ​ ​ ​ ​ Prepaid expenses and other current assets $ (2,109) ​ $ (1,631) ​ $ (3,740) Other changes in operating assets and liabilities ​ (58) ​ ​ (1,633) ​ ​ (1,691) Net cash (used in) provided by operating activities ​ 6,755 ​ ​ (3,264) ​ ​ 3,491 ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from investing activities: ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment additions ​ (13,313) ​ ​ 3,264 ​ ​ (10,049) Net cash used in investing activities ​ (17,561) ​ ​ 3,264 ​ ​ (14,297)
Schedule of supplemental balance sheet information	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ 2023 ​ 2022 Prepaid expenses and other current assets: ​ ​ Prepaid expenses ​ $ 11,558 ​ $ 5,875 Unamortized cloud computing implementation costs ​ ​ 3,995 ​ ​ 1,957 Prepaid insurance ​ ​ 521 ​ ​ 2,291 Prepaid licenses and support ​ ​ 10,099 ​ ​ 12,217 Prepaid expenses and other current assets ​ $ 26,173 ​ $ 22,340 ​ ​ ​ ​ ​ ​ ​ Other assets: ​ ​ ​ ​ Unamortized cloud computing implementation costs ​ $ 12,475 ​ $ 12,721 Other assets ​ ​ 3,538 ​ ​ 2,612 Total other assets ​ $ 16,013 ​ $ 15,333 ​ ​ ​ ​ ​ ​ ​ Accrued expenses: ​ ​ ​ ​ ​ ​ Accrued general expenses ​ $ 25,998 ​ $ 18,485 Accrued contract labor and professional fees ​ ​ 13,372 ​ ​ 17,421 Accrued income and other taxes ​ ​ 5,365 ​ ​ 2,328 Accrued expenses ​ $ 44,735 ​ $ 38,234 ​ ​ ​ ​ ​ ​ ​
Schedule of supplemental cash flow disclosures	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2023 2022 ​ 2021 Cash paid for: ​ ​ ​ ​ Interest ​ $ 3,729 ​ $ 2,221 ​ $ 223 Income taxes, net of refunds ​ ​ 5,652 ​ ​ 3,059 ​ ​ 1,287 Cash paid included in the measurement of lease liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating cash flows from operating leases ​ ​ 4,019 ​ ​ 4,240 ​ ​ 4,692 Non-cash investing and financing activities: ​ ​ ​ ​ ​ ​ ​ Change in settlement value of deferred purchase commitment liability ​ ​ 4,020 ​ ​ 990 ​ ​ — Change in fair value of contingent consideration liability ​ ​ 1,549 ​ ​ 2,300 ​ ​ 300 Estimated distributions payable under Tax Sharing Agreement ​ ​ — ​ ​ — ​ ​ 536 Purchase commitment and contingent consideration liabilities ​ ​ — ​ ​ — ​ ​ 12,736 Deferred purchase consideration ​ ​ — ​ ​ — ​ ​ 39,024 Leased assets obtained in exchange for new finance lease liabilities ​ ​ 124 ​ ​ 1,069 ​ ​ 173

REVENUE RECOGNITION (Tables)

REVENUE RECOGNITION (Tables)	12 Months Ended
	Dec. 31, 2023
REVENUE RECOGNITION
Schedule of disaggregation of revenue	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2023 2022 2021 Software subscriptions: ​ ​ ​ ​ ​ ​ Software licenses ​ $ 266,213 ​ $ 246,577 ​ $ 231,371 Cloud subscriptions ​ ​ 214,617 ​ ​ 168,896 ​ ​ 127,044 Software subscriptions ​ ​ 480,830 ​ ​ 415,473 ​ ​ 358,415 Services ​ 91,557 ​ 76,151 ​ 67,133 Total revenues ​ $ 572,387 ​ $ 491,624 ​ $ 425,548 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Schedule of beginning and ending balances of accounts receivable, net of allowance	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2023 2022 Balance, beginning of period ​ $ 102,885 ​ $ 76,929 Balance, end of period ​ 141,752 ​ 102,885 Increase, net ​ $ 38,867 ​ $ 25,956
Schedule of beginning and ending balances of and changes to the allowance and the deferred allowance	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2023 ​ 2022 ​ 2021 ​ ​ Balance ​ Net Change Balance ​ Net Change ​ Balance ​ ​ Net Change Allowance balance, January 1, ​ $ (9,554) ​ ​ $ (9,151) ​ $ (8,592) ​ ​ ​ Allowance balance, December 31, ​ (16,272) ​ ​ (9,554) ​ ​ (9,151) ​ ​ ​ Change in allowance ​ ​ ​ $ 6,718 ​ ​ ​ $ 403 ​ ​ ​ $ 559 Deferred allowance balance, January 1, ​ 7,133 ​ ​ 6,537 ​ ​ 6,432 ​ ​ ​ Deferred allowance balance, December 31, ​ 11,741 ​ ​ 7,133 ​ ​ 6,537 ​ ​ ​ Change in deferred allowance ​ ​ ​ (4,608) ​ ​ ​ (596) ​ ​ ​ ​ (105) Net amount charged to revenues ​ ​ ​ $ 2,110 ​ ​ ​ $ (193) ​ ​ ​ $ 454 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ ​ 2023 ​ 2022 Balances: ​ ​ ​ Deferred revenue, current ​ $ 290,143 ​ $ 268,847 Deferred revenue, non-current ​ 2,577 ​ 10,289 Total deferred revenue ​ $ 292,720 ​ $ 279,136 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2023 ​ 2022 ​ 2021 Changes to deferred revenue: ​ ​ ​ Beginning balance ​ $ 279,136 ​ $ 249,010 ​ $ 222,262 Additional amounts deferred ​ 585,971 ​ 521,750 ​ 452,296 Revenues recognized ​ (572,387) ​ (491,624) ​ (425,548) Ending balance ​ $ 292,720 ​ $ 279,136 ​ $ 249,010
Schedule of information about the balances of and changes to deferred revenue	​ ​ ​ ​ ​ Year Ending December 31, ​ ​ 2024 ​ $ 290,143 2025 ​ 2,498 2026 ​ 79 Total ​ $ 292,720
Schedule of information about the changes to contract cost balances	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2023 ​ 2022 ​ 2021 Deferred commissions: ​ ​ ​ Beginning balance ​ $ 15,463 ​ $ 12,555 ​ $ 11,743 Additions ​ 16,552 ​ 13,913 ​ 10,018 Amortization ​ (10,778) ​ (11,005) ​ (9,206) Ending balance ​ $ 21,237 ​ $ 15,463 ​ $ 12,555 3. ​ ​

BUSINESS COMBINATIONS (Tables)

BUSINESS COMBINATIONS (Tables)	12 Months Ended
	Dec. 31, 2023
LCR
Business combinations
Schedule of purchase price	​ ​ ​ ​ ​ ​ ​ As of Acquisition Date Cash consideration ​ $ 60,038 Fair value of deferred purchase consideration ​ ​ 39,024 Total ​ $ 99,062
Schedule of purchase price to assets acquired and liabilities assumed	​ ​ ​ ​ ​ ​ ​ As of Acquisition Date Cash and cash equivalents ​ $ 1,899 Accounts receivable ​ ​ 1,586 Prepaid expenses and other current assets ​ ​ 150 Property and equipment ​ ​ 4 Capitalized software ​ ​ 7,700 Goodwill ​ ​ 86,639 Other intangibles ​ ​ 6,500 Accounts payable ​ ​ (19) Accrued expenses ​ ​ (202) Accrued compensation ​ ​ (1,746) Deferred income tax liability ​ ​ (3,630) Deferred revenue ​ ​ (71) Total ​ $ 98,810
Schedule of acquired intangible assets	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 22, 2021 LCR-Dixon Identifiable Intangibles ​ Balance Sheet Location ​ ​ Fair Value ​ Valuation Methodology ​ Estimated Useful Life ​ Discount Rate ​ Trade name ​ Goodwill and other intangible assets (Note 9) ​ $ 200 ​ Relief from royalty method - income approach ​ 6 months ​ 20.0 % Customer relationships ​ Goodwill and other intangible assets (Note 9) ​ $ 6,300 ​ Excess earnings method - income approach ​ 3 years ​ 20.0 % Developed technology ​ Property and equipment, net (Note 6) ​ $ 7,700 ​ Relief from royalty method - income approach ​ 3 years ​ 20.0 %
Taxamo
Business combinations
Schedule of purchase price	​ ​ ​ ​ ​ ​ ​ May 12, 2021 Cash paid at closing ​ $ 190,153 Fair value of acquisition holdback ​ 502 Fair value of the Option ​ ​ 10,034 Total ​ $ 200,689
Schedule of purchase price to assets acquired and liabilities assumed	​ ​ ​ ​ ​ ​ ​ May 12, 2021 Cash and cash equivalents ​ $ 2,441 Funds held for customers ​ ​ 221 Accounts receivable ​ ​ 2,657 Prepaid expenses and other current assets ​ ​ 908 Property and equipment ​ 40,792 Goodwill ​ ​ 164,199 Other intangibles ​ ​ 1,581 Accounts payable ​ ​ (304) Accrued expenses ​ ​ (1,395) Accrued compensation ​ ​ (3,939) Deferred revenue ​ ​ (2,196) Deferred other liabilities ​ ​ (4,276) Total ​ $ 200,689
Schedule of acquired intangible assets	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ May 12, 2021 Taxamo Identifiable Intangibles ​ Balance Sheet Location ​ ​ Fair Value ​ Valuation Methodology ​ Estimated Useful Life ​ Discount Rate ​ Developed technology ​ Property and equipment, net (Note 6) ​ $ 40,746 ​ Multi-period excess earnings method - income approach ​ 3 years ​ 16.5 % Trade name ​ Goodwill and other intangible assets (Note 9) ​ $ 608 ​ Relief from royalty method - income approach ​ 2 years ​ 16.5 % Customer relationships ​ Goodwill and other intangible assets (Note 9) ​ $ 973 ​ Distributor method - income approach ​ 2 years ​ 16.5 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Tellutax
Business combinations
Schedule of purchase price	​ ​ ​ ​ ​ ​ ​ January 25, 2021 Capitalized software - developed technology ​ $ 3,600 Goodwill ​ 4,700 Total ​ $ 8,300

INVESTMENTS (Tables)

INVESTMENTS (Tables)	12 Months Ended
	Dec. 31, 2023
INVESTMENTS
Schedule of amortized cost, gross unrealized gains and losses, allowance for credit losses, and fair value aggregated by major security	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2023 ​ Investment securities available-for-sale: ​ Amortized Cost Gross Unrealized Gain Gross Unrealized Loss ​ Allowance For Credit Losses Fair Value ​ Commercial Paper ​ $ 7,169 ​ $ — ​ $ (1) ​ $ — ​ $ 7,168 ​ U.S. Treasury Securities ​ ​ 3,628 ​ ​ — ​ ​ (7) ​ ​ — ​ ​ 3,621 ​ Total investment securities available-for-sale ​ $ 10,797 ​ $ — ​ $ (8) ​ $ — ​ $ 10,789 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2022 ​ Investment securities available for sale: ​ Amortized Cost Gross Unrealized Gain Gross Unrealized Loss ​ Allowance For Credit Losses Fair Value ​ Commercial paper ​ $ 9,662 ​ $ — ​ $ (2) ​ $ — ​ $ 9,660 ​ U.S. Treasury securities ​ ​ 5,249 ​ ​ — ​ ​ (46) ​ ​ — ​ ​ 5,203 ​ Total investment securities available for sale ​ $ 14,911 ​ $ — ​ $ (48) ​ $ — ​ $ 14,863 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Schedule of length of time of gross unrealized losses and fair value of our securities available for sale	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2023 ​ ​ Less than 12 Months ​ 12 Months or Longer ​ Total Investment securities available-for-sale without an allowance for credit losses: ​ Fair Value Gross Unrealized Loss Fair Value ​ Gross Unrealized Loss Fair Value ​ Gross Unrealized Loss Commercial Paper ​ $ 4,472 ​ ​ (1) ​ $ — ​ $ — ​ $ 4,472 ​ $ (1) U.S. Treasury Securities ​ ​ — ​ ​ — ​ ​ 2,043 ​ ​ (7) ​ ​ 2,043 ​ ​ (7) Total investment securities available-for-sale ​ $ 4,472 ​ $ (1) ​ $ 2,043 ​ $ (7) ​ $ 6,515 ​ $ (8) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2022 ​ ​ Less than 12 Months ​ 12 Months or Longer ​ Total Investment securities available for sale without an allowance for credit losses: ​ Fair Value Gross Unrealized Loss Fair Value ​ Gross Unrealized Loss Fair Value ​ Gross Unrealized Loss Commercial paper ​ $ 6,464 ​ $ (4) ​ $ — ​ $ — ​ $ 6,464 ​ $ (4) U.S. Treasury securities ​ ​ 3,746 ​ ​ (27) ​ ​ 1,457 ​ ​ (19) ​ ​ 5,203 ​ ​ (46) Total investment securities available for sale ​ $ 10,210 ​ $ (31) ​ $ 1,457 ​ $ (19) ​ $ 11,667 ​ $ (50)
Schedule of fair value of our investment securities by major security type and contractual maturity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2023 ​ ​ ​ Due in 1 Year or Less Due > 1 Year through 5 Years Due > 5 Years through 10 Years ​ Due > 10 Years Total ​ Fair value of investment securities available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial Paper ​ $ 7,168 ​ $ — ​ $ — ​ $ — ​ $ 7,168 ​ U.S. Treasury Securities ​ ​ 1,279 ​ ​ 2,342 ​ ​ — ​ ​ — ​ ​ 3,621 ​ Total investment securities available-for-sale ​ $ 8,447 ​ $ 2,342 ​ $ — ​ $ — ​ $ 10,789 ​ Amortized cost of investment securities available-for-sale ​ $ 8,450 ​ $ 2,347 ​ $ — ​ $ — ​ $ 10,797 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

FINANCIAL INSTRUMENTS AND FAI_2

FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS (Tables)	12 Months Ended
	Dec. 31, 2023
FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS
Schedule of assets and liabilities measured at fair value on a recurring basis	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements Using As of December 31, 2023 ​ Fair Value Prices in active markets for identical assets (Level 1) Significant other observable inputs (Level 2) Significant unobservable inputs (Level 3) Money Market Funds ​ $ 53,049 ​ $ 53,049 ​ $ — ​ $ — Commercial Paper ​ ​ 7,168 ​ ​ — ​ ​ 7,168 ​ ​ — U.S. Treasury Securities ​ ​ 3,621 ​ ​ — ​ ​ 3,621 ​ ​ — Tellutax Contingent Consideration ​ ​ 4,900 ​ ​ — ​ ​ — ​ ​ 4,900 Foreign Currency Forward Contracts ​ ​ 849 ​ ​ — ​ ​ 849 ​ ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements Using As of December 31, 2022 ​ Fair Value Prices in active markets for identical assets (Level 1) Significant other observable inputs (Level 2) Significant unobservable inputs (Level 3) Money Market Funds ​ $ 67,430 ​ $ 67,430 ​ $ — ​ $ — Commercial Paper ​ ​ 9,660 ​ ​ — ​ ​ 9,660 ​ ​ — U.S. Treasury Securities ​ ​ 5,203 ​ ​ — ​ ​ 5,203 ​ ​ — Tellutax Contingent Consideration ​ ​ 4,800 ​ ​ — ​ ​ — ​ ​ 4,800 Foreign Currency Forward Contracts ​ ​ 569 ​ ​ — ​ ​ 569 ​ ​ —
Summary of estimated fair value of Tellutax contingent consideration	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2023 Liability Fair Value Valuation Technique Unobservable Inputs Tellutax Contingent Consideration ​ $ 4,900 ​ Monte Carlo Simulation ​ Revenue volatility ​ 60.0 % ​ ​ ​ ​ ​ ​ ​ Revenue discount rate ​ 20.8 % ​ ​ ​ ​ ​ ​ ​ Term (in years) ​ 1.3 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 Liability Fair Value Valuation Technique Unobservable Inputs Tellutax Contingent Consideration ​ $ 4,800 ​ Monte Carlo Simulation ​ Revenue volatility ​ 75.0 % ​ ​ ​ ​ ​ ​ ​ Revenue discount rate ​ 22.4 % ​ ​ ​ ​ ​ ​ ​ Term (in years) ​ 2.4 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Changes in fair value of Tellutax contingent consideration	​ ​ ​ ​ ​ ​ ​ Tellutax ​ ​ Contingent ​ ​ Consideration ​ ​ ​ Balance, January 1, 2021 ​ $ — Acquisition of Tellutax ​ ​ 2,200 Fair value adjustments ​ ​ 300 Balance, December 31, 2021 ​ ​ 2,500 Fair value adjustments ​ ​ 2,300 Balance, December 31, 2022 ​ ​ 4,800 Fair value adjustments ​ ​ 1,549 Payments ​ ​ (1,449) Balance, December 31, 2023 ​ $ 4,900

PROPERTY AND EQUIPMENT (Tables)

PROPERTY AND EQUIPMENT (Tables)	12 Months Ended
	Dec. 31, 2023
PROPERTY AND EQUIPMENT
Schedule of major components of property and equipment	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ ​ 2023 ​ 2022 ​ ​ ​ ​ ​ Leasehold improvements ​ $ 20,662 ​ $ 20,929 Equipment ​ 22,012 ​ 39,238 Computer software purchased ​ 2,690 ​ 11,892 Internal-use software developed: ​ ​ ​ ​ Cloud-based customer solutions ​ 142,302 ​ 142,980 Internal systems and tools ​ 39,430 ​ 42,035 Furniture and fixtures ​ 7,669 ​ 7,665 In-process internal-use software ​ 28,883 ​ 18,200 Property and equipment ​ 263,648 ​ 282,939 Less accumulated depreciation and amortization ​ (162,914) ​ (181,849) Property and equipment, net ​ $ 100,734 ​ $ 101,090
Schedule of major components of internal-use software	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ ​ 2023 ​ 2022 ​ ​ ​ ​ Internal-use software developed ​ $ 181,732 ​ $ 185,015 Less accumulated depreciation ​ (121,646) ​ (119,603) Internal-use software developed, net of accumulated depreciation ​ 60,086 ​ 65,412 In-process internal-use software ​ 28,883 ​ 18,200 Internal-use software developed, net ​ $ 88,969 ​ $ 83,612
Schedule of amounts capitalized for internal-use software and included in property and equipment additions on the consolidated statements of cash flows	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2023 ​ 2022 ​ 2021 Cloud-based customer solutions $ 29,496 $ 28,918 $ 19,837 Internal systems and tools 17,751 ​ 13,356 ​ 9,811 Total $ 47,247 ​ $ 42,274 ​ $ 29,648
Schedule of amortization expense internally developed software	​ ​ ​ ​ ​ ​ ​ ​ Year Ending December 31, Internal Systems and Tools Cloud-Based Customer Solutions 2024 ​ $ 8,982 ​ $ 25,151 2025 ​ 6,787 ​ ​ 12,822 2026 ​ 1,615 ​ ​ 3,901 2027 ​ 621 ​ ​ — 2028 ​ 207 ​ ​ — Total ​ $ 18,212 ​ $ 41,874 ​

CAPITALIZED SOFTWARE (Tables)

CAPITALIZED SOFTWARE (Tables)	12 Months Ended
	Dec. 31, 2023
CAPITALIZED SOFTWARE
Schedule of major components of capitalized software	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ 2023 ​ 2022 Capitalized software ​ $ 115,152 ​ $ 96,577 Less accumulated amortization ​ (81,410) ​ (62,197) Capitalized software, net of accumulated depreciation ​ 33,742 ​ 34,380 In-process capitalized software ​ 5,029 ​ 4,632 Capitalized software, net ​ $ 38,771 ​ $ 39,012
Schedule of in process capitalized software not available for general release	​ ​ ​ ​ ​ Year Ending December 31, ​ 2024 ​ $ 19,143 2025 ​ 10,689 2026 ​ 3,880 2027 ​ 30 2028 ​ — Total ​ $ 33,742 ​

LEASES (Tables)

LEASES (Tables)	12 Months Ended
	Dec. 31, 2023
LEASES
Schedule of company's lease assets and lease liabilities and their balance sheet location	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ Balance Sheet Location ​ 2023 2022 Lease assets: ​ ​ ​ ​ ​ ​ Operating lease right-of-use assets ​ Operating lease right-of-use assets ​ $ 14,605 ​ $ 17,187 Finance lease assets ​ Property and equipment, net (Note 6) ​ ​ 107 ​ ​ 600 Total lease assets ​ ​ ​ $ 14,712 ​ $ 17,787 ​ ​ ​ ​ ​ ​ ​ ​ ​ Lease liabilities: ​ ​ ​ ​ ​ ​ ​ ​ Current: ​ ​ ​ ​ ​ ​ ​ ​ Operating lease liabilities ​ Current portion of operating lease liabilities ​ $ 3,717 ​ $ 4,086 Finance lease liabilities ​ Current portion of finance lease liabilities ​ ​ 74 ​ ​ 103 Total current lease liabilities ​ ​ ​ $ 3,791 ​ $ 4,189 Non-current: ​ ​ ​ ​ ​ ​ ​ ​ Operating lease liabilities ​ Operating lease liabilities, net of current portion ​ $ 16,567 ​ $ 20,421 Finance lease liabilities ​ Finance lease liabilities, net of current portion ​ ​ 51 ​ ​ 10 Total non-current lease liabilities ​ ​ ​ ​ 16,618 ​ ​ 20,431 Total lease liabilities ​ ​ ​ $ 20,409 ​ $ 24,620
Schedule of company's lease costs, weighted-average term and rate	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2023 ​ 2022 ​ 2021 ​ ​ ​ ​ ​ ​ Operating lease cost $ 4,019 ​ $ 3,714 ​ $ 4,774 ​ ​ ​ ​ ​ ​ ​ ​ ​ Finance lease cost: ​ ​ ​ ​ ​ ​ ​ ​ Amortization of lease assets ​ 788 ​ ​ 1,275 ​ ​ 931 Interest on lease liabilities ​ 8 ​ ​ 18 ​ ​ 16 Total lease cost $ 4,815 ​ $ 5,007 ​ $ 5,721 ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ ​ 2023 ​ 2022 ​ Weighted-average remaining lease term (years): ​ ​ ​ ​ Operating leases 4.7 ​ 5.7 ​ Finance leases 2.1 ​ 0.5 ​ ​ ​ ​ ​ ​ Weighted-average discount rate: ​ ​ ​ ​ Operating leases 2.3 % 2.3 % Finance leases 5.6 % 2.3 %
Schedule of maturity of operating lease liabilities	​ Lease liability maturities for the next five years and thereafter are as follows as of December 31, 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating Leases Finance Leases ​ 2024 ​ $ 4,228 ​ $ 75 ​ 2025 ​ ​ 4,493 ​ ​ 45 ​ 2026 ​ ​ 4,565 ​ ​ 11 ​ 2027 ​ ​ 4,636 ​ ​ — ​ 2028 ​ ​ 3,494 ​ ​ — ​ Thereafter ​ ​ — ​ ​ — ​ Total lease payments ​ ​ 21,416 ​ ​ 131 ​ Less: Imputed interest ​ ​ (1,132) ​ ​ (6) ​ Present value of lease liabilities ​ $ 20,284 ​ $ 125 ​ ​
Schedule of maturity of finance lease liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating Leases Finance Leases ​ 2024 ​ $ 4,228 ​ $ 75 ​ 2025 ​ ​ 4,493 ​ ​ 45 ​ 2026 ​ ​ 4,565 ​ ​ 11 ​ 2027 ​ ​ 4,636 ​ ​ — ​ 2028 ​ ​ 3,494 ​ ​ — ​ Thereafter ​ ​ — ​ ​ — ​ Total lease payments ​ ​ 21,416 ​ ​ 131 ​ Less: Imputed interest ​ ​ (1,132) ​ ​ (6) ​ Present value of lease liabilities ​ $ 20,284 ​ $ 125 ​ ​

GOODWILL AND OTHER INTANGIBLE_2

GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)	12 Months Ended
	Dec. 31, 2023
GOODWILL AND OTHER INTANGIBLE ASSETS
Changes in the carrying amount of goodwill	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ ​ 2023 ​ 2022 Goodwill ​ $ 257,842 ​ $ 251,842 Other intangible assets, net ​ ​ 2,396 ​ 5,181 Total ​ $ 260,238 ​ $ 257,023 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ ​ 2023 ​ 2022 Balance, January 1 ​ $ 251,842 ​ $ 270,041 Measurement period adjustments ​ ​ — ​ ​ (10,329) Foreign currency translation adjustments ​ ​ 6,000 ​ ​ (7,870) Balance, December 31, gross ​ ​ 257,842 ​ ​ 251,842 Accumulated impairment losses ​ ​ — ​ ​ — Balance, December 31, net ​ $ 257,842 ​ $ 251,842
Schedule of acquired intangible assets	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ ​ ​ ​ ​ ​ ​ ​ 2023 ​ 2022 Weighted average amortization period (years) ​ ​ ​ ​ ​ 3.5 ​ ​ 3.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2023 ​ ​ As of December 31, 2022 ​ ​ ​ Gross Carrying Amount ​ ​ Accumulated Amortization ​ ​ Gross Carrying Amount ​ ​ Accumulated Amortization Customer relationships ​ $ 8,348 ​ $ 6,385 ​ $ 8,225 ​ $ 3,855 Trademarks and tradenames ​ ​ 1,303 ​ ​ 1,119 ​ ​ 1,240 ​ ​ 887 Developed technology ​ ​ 1,309 ​ ​ 1,060 ​ ​ 1,202 ​ ​ 744 Total ​ $ 10,960 ​ $ 8,564 ​ $ 10,667 ​ $ 5,486 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ ​ Cost of Revenues, Software Subscriptions ​ Selling and Marketing Expense ​ ​ Total Expense 2023 ​ ​ ​ $ 243 $ 2,641 ​ $ 2,884 2022 ​ ​ ​ ​ ​ 234 ​ ​ 3,779 ​ ​ 4,013 2021 ​ ​ ​ ​ ​ 253 ​ ​ 813 ​ ​ 1,066 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Schedule of future amortization expense	​ ​ ​ ​ ​ Year Ending December 31, ​ 2024 ​ $ 2,110 2025 ​ 286 Total ​ $ 2,396

DEBT (Tables)

DEBT (Tables)	12 Months Ended
	Dec. 31, 2023
DEBT
Schedule of Debt	​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ ​ 2023 ​ ​ 2022 Term Loan $ 2,500 ​ $ 2,188 Current portion of long-term debt ​ 2,500 ​ ​ 2,188 ​ ​ ​ ​ ​ ​ Term Loan ​ 44,375 ​ ​ 46,875 Deferred financing costs ​ (316) ​ ​ (166) Debt, net of current portion $ 44,059 ​ $ 46,709 Total debt $ 46,559 ​ $ 48,897
Schedule of debt maturities	​ ​ ​ ​ ​ Year Ending December 31, ​ ​ ​ 2024 ​ $ 2,500 2025 ​ ​ 2,500 2026 ​ ​ 3,437 2027 ​ ​ 38,438 Total debt, net of financing costs ​ $ 46,875 ​

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	12 Months Ended
	Dec. 31, 2023
Class A
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Schedule of earnings per share basic and diluted	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ Class A common stock: 2023 ​ 2022 ​ 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Numerator, basic: ​ ​ ​ ​ ​ Net loss attributable to all stockholders $ (13,093) ​ $ (12,304) ​ $ (1,479) ​ Class A common stock as a percentage of total shares outstanding, basic 36.06 % 30.65 % 24.12 % Net loss attributable to Class A stockholders, basic $ (4,721) ​ $ (3,771) ​ $ (357) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Numerator, diluted: ​ ​ ​ ​ ​ Net loss attributable to all stockholders $ (13,093) ​ $ (12,304) ​ $ (1,479) ​ Class A common stock as a percentage of total shares outstanding, diluted 36.06 % 30.65 % 24.12 % Net loss attributable to Class A stockholders, diluted $ (4,721) ​ $ (3,771) ​ $ (357) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Denominator, basic and diluted: ​ ​ ​ Weighted average Class A common stock, basic 54,753 ​ 45,864 ​ 35,647 ​ Dilutive effect of common stock equivalents (1) (2) (3) — ​ — ​ — ​ Weighted average Class A common stock, diluted 54,753 ​ 45,864 ​ 35,647 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net loss per Class A share, basic $ (0.09) ​ $ (0.08) ​ $ (0.01) ​ Net loss per Class A share, diluted $ (0.09) ​ $ (0.08) ​ $ (0.01) ​ 1) . ​ 2) . ​ 3)
Class B
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Schedule of earnings per share basic and diluted	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ Class B common stock: 2023 ​ 2022 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Numerator, basic: ​ ​ ​ Net loss attributable to all stockholders $ (13,093) ​ $ (12,304) ​ $ (1,479) ​ Class B common stock as a percentage of total shares outstanding, basic 63.94 % 69.35 % 75.88 % Net loss attributable to Class B stockholders, basic $ (8,372) ​ $ (8,533) ​ $ (1,122) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Numerator, diluted: ​ ​ ​ Net loss attributable to all stockholders $ (13,093) ​ $ (12,304) ​ $ (1,479) ​ Class B common stock as a percentage of total shares outstanding, diluted 63.94 % 69.35 % 75.88 % Net loss attributable to Class B stockholders, diluted $ (8,372) ​ $ (8,533) ​ $ (1,122) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Denominator, basic and diluted: ​ ​ ​ Weighted average Class B common stock, basic 97,106 ​ 103,781 ​ 112,133 ​ Dilutive effect of common stock equivalents — ​ — ​ — ​ Weighted average Class B common stock, diluted 97,106 ​ 103,781 ​ 112,133 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net loss per Class B share, basic $ (0.09) ​ $ (0.08) ​ $ (0.01) ​ Net loss per Class B share, diluted $ (0.09) ​ $ (0.08) ​ $ (0.01) ​ ​

EMPLOYEE BENEFIT AND DEFERRED_2

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS (Tables)	12 Months Ended
	Dec. 31, 2023
Compensation plans:
Schedule of ESPP valuation assumptions	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Offering Period Ending ​ 5/31/2024 ​ 11/30/2023 ​ 5/31/2023 ​ 11/30/2022 ​ 5/31/2022 ​ Fair market value of common stock $ 27.82 ​ $ 21.76 ​ $ 17.21 ​ $ 11.16 ​ $ 17.38 ​ Volatility 36.6 % 39.4 % 46.4 % 35.4 % 37.3 % Expected term (years) 0.5 ​ 0.5 ​ 0.5 ​ 0.5 ​ 0.5 ​ Expected dividend yield - % - % - % - % - % Risk-free interest rate 5.3 % 5.4 % 4.7 % 1.6 % 0.1 %
Schedule of stock-based compensation cost related to incentive awards	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2023 2022 2021 Stock-based compensation expense: ​ ​ ​ ​ ​ ​ ​ ​ ​ Stock options ​ $ 6,349 ​ $ 7,081 ​ $ 17,533 RSUs ​ 24,257 ​ 9,286 ​ 2,964 RSAs ​ 2,496 ​ 2,768 ​ 5,126 ESPP ​ ​ 817 ​ ​ 594 ​ ​ 537 Total stock-based compensation expense ​ $ 33,919 ​ $ 19,729 ​ $ 26,160 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Schedule of stock based compensation cost in consolidated statement of operations	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2023 2022 2021 Stock-based compensation expense: ​ ​ ​ ​ ​ ​ ​ ​ Cost of revenues, software subscriptions $ 2,834 ​ $ 2,090 $ 2,336 Cost of revenues, services 1,846 ​ 1,433 2,648 Research and development 5,994 ​ 1,798 2,620 Selling and marketing 8,380 ​ 6,284 6,371 General and administrative 14,865 ​ 8,124 ​ ​ 12,185 Total stock-based compensation expense $ 33,919 ​ $ 19,729 ​ $ 26,160
Employee Stock Option [Member]
Compensation plans:
Schedule of Option activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ Average ​ ​ ​ ​ ​ ​ ​ Average ​ Remaining ​ Aggregate ​ ​ ​ ​ ​ Exercise ​ Contractual ​ Intrinsic 2020 Plan Option Activity ​ Units ​ ​ Price ​ Life (Years) ​ Value Outstanding at January 1, 2023 ​ 8,508 ​ $ 4.34 ​ 4.3 ​ $ 86,514 Exercised ​ (2,782) ​ $ 2.32 ​ ​ ​ ​ ​ Forfeited ​ (34) ​ $ 5.82 ​ ​ ​ ​ ​ 2020 Plan options outstanding at December 31, 2023 ​ 5,692 ​ $ 5.32 ​ 4.7 ​ ​ 124,327 2020 Plan options exercisable at December 31, 2023 4,289 ​ $ 4.31 4.1 ​ ​ 97,737 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Schedule of outstanding, vested and exercisable	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Options Outstanding ​ Options Vested and Exercisable ​ ​ Weighted ​ Weighted ​ ​ ​ ​ Average ​ ​ ​ Average Exercise Prices ​ Units ​ Life (Years) ​ Units ​ Life (Years) $0.15 to $0.71 786 ​ * ​ 786 ​ * $2.15 147 ​ 1.1 ​ 147 ​ 1.1 $2.50 1,721 ​ 2.7 ​ 1,721 ​ 2.7 $2.67 63 ​ 3.1 ​ 63 ​ 3.1 $3.17 431 ​ 4.4 ​ 431 ​ 4.4 $3.73 ​ 1,236 ​ 5.8 ​ 490 ​ 5.8 $4.70 ​ 603 ​ 6.1 ​ 261 ​ 6.1 $18.47 ​ 213 ​ 7.9 ​ 107 ​ 7.9 $18.96 ​ 185 ​ 7.6 ​ 120 ​ 7.6 $19.00 65 ​ 7.7 ​ 32 ​ 7.7 $32.16 242 ​ 7.2 ​ 131 ​ 7.2 ​ ​ 5,692 ​ ​ 4,289 ​ ​ *These Options have indefinite contractual lives. ​ ​ ​ ​ ​ ​ ​
Schedule of valuation assumptions	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Option Valuation Period ​ ​ Q4 2021 Q3 2021 ​ Q3 2021 Q2 2021 Q1 2021 Fair market value of common stock $ 18.47 ​ $ 18.96 ​ ​ $ 19.00 ​ $ 17.66 ​ $ 32.16 ​ Volatility 37.4 % 37.1 % ​ 37.1 % 36.8 % 36.8 % Expected term (years) 5.0 ​ ​ 5.0 ​ ​ 5.0 ​ ​ 6.0 ​ ​ 6.0 ​ Expected dividend yield — % ​ — % ​ — % ​ — % ​ — % Risk-free interest rate 1.3 % ​ 0.8 % ​ 0.9 % ​ 0.4 % ​ 0.4 %
Restricted Stock Units
Compensation plans:
Schedule of restricted activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ ​ ​ Grant Date Fair ​ ​ Units ​ Value Per Share Outstanding at January 1, 2023 ​ 2,562 ​ $ 15.90 Granted ​ 2,627 ​ ​ 16.64 Vested ​ (796) ​ ​ 17.45 Forfeited ​ (222) ​ ​ 15.23 Outstanding at December 31, 2023 ​ 4,171 ​ $ 16.11
Restricted Stock Awards
Compensation plans:
Schedule of restricted activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ ​ ​ Grant Date Fair ​ ​ Units ​ Value Per Share Outstanding at January 1, 2023 ​ 235 ​ $ 14.91 Granted 62 ​ ​ 22.69 Vested (206) ​ 14.32 Outstanding at December 31, 2023 91 ​ $ 21.50

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	12 Months Ended
	Dec. 31, 2023
COMMITMENTS AND CONTINGENCIES
Schedule of future minimum payments for non-cancelable agreements with third-party providers	​ ​ ​ ​ 2024 $ 10,450 2025 ​ 7,452 2026 ​ 4,568 2027 ​ 3,696 2028 ​ 3,075 ​ $ 29,241

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2023
INCOME TAXES
Schedule of components of net income (loss) before income taxes	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2023 2022 2021 U.S. ​ $ (3,126) ​ $ 5,827 ​ $ 5,608 Foreign ​ (18,548) ​ (15,957) ​ (9,534) Net loss before income taxes ​ $ (21,674) ​ $ (10,130) ​ $ (3,926)
Schedule of Income tax benefit (expense)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2023 2022 2021 Current income taxes: ​ ​ ​ Federal ​ $ (279) ​ $ 1,696 ​ $ — State and local ​ ​ 1,568 ​ ​ 1,068 ​ ​ 155 Foreign ​ 1,347 ​ 577 ​ 468 Total current ​ 2,636 ​ 3,341 ​ 623 Deferred income taxes: ​ ​ ​ Federal ​ ​ (9,224) ​ ​ 904 ​ ​ (1,849) State and local ​ (1,552) ​ 72 ​ (7) Foreign ​ (441) ​ (2,143) ​ (1,214) Total deferred ​ (11,217) ​ (1,167) ​ (3,070) Income tax expense (benefit) ​ $ (8,581) ​ $ 2,174 ​ $ (2,447)
Schedule of reconciliation of the effective tax rate to tax	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2023 2022 2021 ​ ​ Total ​ Tax Rate ​ Total ​ Tax Rate Total ​ Tax Rate Pretax net loss ​ $ (21,674) ​ $ (10,130) ​ $ (3,926) ​ Taxes: ​ ​ ​ ​ ​ ​ U.S. federal income tax at statutory rate ​ $ (4,552) 21.0 % $ (2,128) 21.0 % $ (825) 21.0 % State income taxes ​ ​ 289 (1.3) % ​ 441 (4.4) % ​ 678 (17.3) % Stock-based compensation expense ​ ​ (6,236) ​ 28.8 % ​ 1,787 ​ (17.6) % ​ (4,550) ​ 115.9 % Impact of foreign operations ​ 1,463 ​ (6.8) % 1,352 ​ (13.3) % 954 ​ (24.3) % Transaction costs ​ ​ — ​ 0.0 % ​ 176 ​ (1.7) % ​ 1,082 ​ (27.6) % U.S. taxation of foreign earnings ​ ​ (245) ​ 1.1 % ​ (179) ​ 1.8 % ​ 144 ​ (3.7) % Nondeductible compensation ​ ​ 2,822 ​ (13.0) % ​ 485 ​ (4.8) % ​ 682 ​ (17.4) % Tax credits ​ ​ (5,818) ​ 26.8 % ​ (341) ​ 3.4 % ​ (488) ​ 12.4 % Change in valuation allowance ​ ​ 3,386 ​ (15.6) % ​ 427 ​ (4.2) % ​ 373 ​ (9.5) % Changes in prior year unrecognized tax benefits ​ ​ 451 ​ (2.1) % ​ — ​ 0.0 % ​ — ​ 0.0 % Other permanent items, net ​ ​ (141) 0.7 % ​ 154 (1.7) % ​ (497) 12.8 % Taxes and effective tax rate ​ $ (8,581) 39.6 % $ 2,174 (21.5) % $ (2,447) 62.3 %
Schedule of significant components of the Company's net deferred tax assets (liabilities)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, Deferred tax assets: 2023 2022 Deferred revenue ​ $ 3,523 ​ $ 2,981 State operating loss carry forwards ​ 2,682 ​ 2,831 Federal and foreign loss carry forwards ​ 4,361 ​ 11,318 Accrued expenses ​ 2,239 ​ 2,238 Accrued compensation ​ 2,339 ​ — Deferred and stock-based compensation ​ 19,008 ​ 23,634 Operating lease liabilities ​ ​ 5,151 ​ ​ 6,272 Tax credits ​ ​ 3,662 ​ ​ — Depreciation and amortization ​ ​ 6,417 ​ ​ — Other ​ 2,721 ​ — Deferred tax assets ​ 52,103 ​ 49,274 Valuation allowance ​ (5,941) ​ (2,285) Total deferred tax assets ​ 46,162 ​ 46,989 Deferred tax liabilities: ​ ​ Depreciation and amortization ​ — ​ (9,337) Prepaid expenses ​ ​ (1,026) ​ ​ (1,256) Right of use asset ​ (3,428) ​ (4,325) Accrued compensation ​ ​ — ​ ​ (1,434) Other ​ ​ — ​ ​ (115) Total deferred tax liabilities ​ (4,454) ​ (16,467) Net deferred tax asset ​ $ 41,708 ​ $ 30,522 ​ ​ ​ ​ ​ ​ ​ Classification in the consolidated balance sheets: ​ ​ ​ ​ ​ ​ Deferred income tax asset ​ $ 41,708 ​ $ 30,938 Deferred other liabilities ​ ​ — ​ ​ (416) Net deferred tax asset ​ $ 41,708 ​ $ 30,522

SUMMARY OF SIGNIFICANT ACCOUN_4

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) item segment	Dec. 31, 2022 USD ($)
Accounting policies:
Self-insurance accruals | $	$ 2,246	$ 2,219
Reporting units | item	1
Operating segments | segment	1
Minimum
Accounting policies:
Capitalized software development cost amortization extension term	2 years
Capitalized Software Development Costs, Amortization Term	3 years
Maximum
Accounting policies:
Capitalized software development cost amortization extension term	5 years
Capitalized Software Development Costs, Amortization Term	5 years
Systax
Accounting policies:
Ownership (as a percent)	80%	65%

SUMMARY OF SIGNIFICANT ACCOUN_5

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revised balance sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021
Revision of Previously Issued Financial Statements
Prepaid expenses and other current assets	$ 26,173	$ 26,124	$ 22,340
Total current assets	266,621	235,023	243,146
Property and equipment, net of accumulated depreciation	100,734	99,502	101,090	$ 98,016	$ 98,858	$ 97,586	$ 96,710
Other assets	$ 16,013	16,975	15,333	13,529	10,260	7,800	3,580
As Reported
Revision of Previously Issued Financial Statements
Prepaid expenses and other current assets		22,536	20,383
Total current assets		231,435	241,189
Property and equipment, net of accumulated depreciation		117,444	115,768	109,123	106,526	102,228	98,390
Other assets		2,621	2,612	2,422	2,592	3,158	1,900
Revision
Revision of Previously Issued Financial Statements
Prepaid expenses and other current assets		3,588	1,957
Total current assets		3,588	1,957
Property and equipment, net of accumulated depreciation		(17,942)	(14,678)	(11,107)	(7,668)	(4,642)	(1,680)
Other assets		$ 14,354	$ 12,721	$ 11,107	$ 7,668	$ 4,642	$ 1,680

SUMMARY OF SIGNIFICANT ACCOUN_6

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revised statements of cash flows (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended	9 Months Ended	12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Jun. 30, 2022	Sep. 30, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities:
Prepaid expenses and other current assets	$ (3,740)				$ (6,354)	$ (2,171)	$ (5,192)
Other changes in operating assets and liabilities	(1,691)	$ (3,912)	$ (6,445)	$ (9,776)	1,156	(11,624)	(1,344)
Net cash (used in) provided by operating activities	3,491	(367)	8,588	23,599	74,332	63,848	90,289
Cash flows from investing activities:
Property and equipment additions	(10,049)	(10,911)	(21,839)	(33,546)	(49,261)	(45,532)	(31,706)
Net cash used in investing activities	(14,297)	14,297	35,182	50,435	$ (66,171)	(72,048)	(294,778)
As Reported
Cash flows from operating activities:
Prepaid expenses and other current assets	(2,109)					(214)
Other changes in operating assets and liabilities	(58)	(950)	(457)	(349)		(583)	336
Net cash (used in) provided by operating activities	6,755	2,595	14,576	33,026		76,846	91,969
Cash flows from investing activities:
Property and equipment additions	(13,313)	(13,873)	(27,827)	(42,973)		(58,530)	(33,386)
Net cash used in investing activities	(17,561)	17,259	41,170	59,862		(85,046)	(296,458)
Revision
Cash flows from operating activities:
Prepaid expenses and other current assets	(1,631)					(1,957)
Other changes in operating assets and liabilities	(1,633)	(2,962)	(5,988)	(9,427)		(11,041)	(1,680)
Net cash (used in) provided by operating activities	(3,264)	(2,962)	(5,988)	(9,427)		(12,998)	(1,680)
Cash flows from investing activities:
Property and equipment additions	3,264	2,962	5,988	9,427		12,998	1,680
Net cash used in investing activities	$ 3,264	$ (2,962)	$ (5,988)	$ (9,427)		$ 12,998	$ 1,680

SUMMARY OF SIGNIFICANT ACCOUN_7

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Concentration of Credit Risk (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) item	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Mar. 31, 2023 USD ($)	Sep. 30, 2022 USD ($)	Jun. 30, 2022 USD ($)	Mar. 31, 2022 USD ($)
Segment information:
Number of banks | item	4
Property and equipment	$ 100,734	$ 101,090	$ 96,710	$ 99,502	$ 98,016	$ 98,858	$ 97,586
Geographic Concentration Risk | Outside United States
Segment information:
Property and equipment	$ 633	$ 827
Revenue | Geographic Concentration Risk | Outside United States
Segment information:
Risk percentage	8%	8%	7%
Revenue | No customer concentration >10% | Outside United States
Segment information:
Risk percentage	0%	0%	0%

SUMMARY OF SIGNIFICANT ACCOUN_8

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Useful life (Details)	Dec. 31, 2023
Leasehold improvements | Minimum
Property and equipment
Estimated useful lives (in years)	1 year
Leasehold improvements | Maximum
Property and equipment
Estimated useful lives (in years)	12 years
Internal-use software | Minimum
Property and equipment
Estimated useful lives (in years)	3 years
Internal-use software | Maximum
Property and equipment
Estimated useful lives (in years)	5 years
Computer software purchased | Minimum
Property and equipment
Estimated useful lives (in years)	3 years
Computer software purchased | Maximum
Property and equipment
Estimated useful lives (in years)	7 years
Equipment | Minimum
Property and equipment
Estimated useful lives (in years)	3 years
Equipment | Maximum
Property and equipment
Estimated useful lives (in years)	10 years
Furniture and fixtures | Minimum
Property and equipment
Estimated useful lives (in years)	7 years
Furniture and fixtures | Maximum
Property and equipment
Estimated useful lives (in years)	10 years

SUMMARY OF SIGNIFICANT ACCOUN_9

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Stock-Based Compensation (Details)	12 Months Ended
	Dec. 31, 2023
ESPP
Compensation plans:
Discount	15%

SUMMARY OF SIGNIFICANT ACCOU_10

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revenue Recognition (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Payment terms (in days)	30-60 days
Reimbursable costs	$ 17	$ 133	$ 14
Advertising expense	$ 26,000	$ 26,529	$ 20,386

SUMMARY OF SIGNIFICANT ACCOU_11

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Foreign Currency (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Other operating expense (income), net
Foreign currency
Net foreign transaction gains (losses)	$ (109)	$ (38)	$ 183

SUMMARY OF SIGNIFICANT ACCOU_12

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Capitalized Costs and Supplemental Balance Sheet Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022
Cloud computing implementation costs
Amortization of cloud computing implementation costs	$ 2,570	$ 0	$ 0
Prepaid expenses and other current assets:
Prepaid expenses	11,558	5,875
Unamortized cloud computing implementation costs	3,995	1,957
Prepaid Insurance	521	2,291
Prepaid licenses and support	10,099	12,217
Prepaid expenses and other current assets	26,173	22,340		$ 26,124
Other assets:
Unamortized cloud computing implementation costs	12,475	12,721
Other assets	3,538	2,612
Total other assets	16,013	15,333	$ 3,580	$ 16,975	$ 13,529	$ 10,260	$ 7,800
Accrued expenses:
Accrued general expenses	25,998	18,485
Accrued contract labor and professional fees	13,372	17,421
Accrued income and other taxes	5,365	2,328
Accrued expenses	$ 44,735	$ 38,234

SUMMARY OF SIGNIFICANT ACCOU_13

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Supplemental Cash Flow Disclosures (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Cash paid for Interest	$ 3,729	$ 2,221	$ 223
Cash paid for income taxes, net of refunds	5,652	3,059	1,287
Cash paid included in the measurement of lease liabilities:
Operating cash flows from operating leases	4,019	4,240	4,692
Non-cash investing and financing activities:
Change in settlement value of deferred purchase commitment liability	4,020	990
Change in fair value of contingent consideration liabilities	1,549	2,300	300
Estimated distributions payable under Tax Sharing Agreement			536
Purchase commitment and contingent consideration liabilities			12,736
Deferred purchase consideration			39,024
Leased assets obtained in exchange for new finance lease liabilities	$ 124	$ 1,069	$ 173

REVENUE RECOGNITION - Disaggreg

REVENUE RECOGNITION - Disaggregation of revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of revenue:
Total revenues	$ 572,387	$ 491,624	$ 425,548
Software subscriptions
Disaggregation of revenue:
Total revenues	480,830	415,473	358,415
Software licenses
Disaggregation of revenue:
Total revenues	266,213	246,577	231,371
Cloud subscriptions
Disaggregation of revenue:
Total revenues	214,617	168,896	127,044
Services
Disaggregation of revenue:
Total revenues	$ 91,557	$ 76,151	$ 67,133

REVENUE RECOGNITION - Accounts

REVENUE RECOGNITION - Accounts receivable, net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
REVENUE RECOGNITION
Allowance for accounts receivable	$ 16,272	$ 9,554	$ 9,151	$ 8,592
Allowance for credit loss
Balance, beginning of period	102,885	76,929
Balance, end of period	141,752	102,885
Increase, net	$ 38,867	$ 25,956

REVENUE RECOGNITION - Allowance

REVENUE RECOGNITION - Allowance and deferred allowance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Allowance for credit loss
Beginning balance	$ (9,554)	$ (9,151)	$ (8,592)
Ending balance	(16,272)	(9,554)	(9,151)
Change in allowance	6,718	403	559
Deferred beginning balance	7,133	6,537	6,432
Deferred ending balance	11,741	7,133	6,537
Change in deferred allowance	(4,608)	(596)	(105)
Net amount charged to revenues	2,110	(193)	454
Revenue recognized for satisfaction	$ 268,847	$ 237,344	$ 207,560

REVENUE RECOGNITION - Deferred

REVENUE RECOGNITION - Deferred revenue (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
REVENUE RECOGNITION
Deferred revenue, current	$ 290,143	$ 268,847
Deferred revenue, non-current	2,577	10,289
Total deferred revenue	$ 292,720	$ 279,136	$ 249,010	$ 222,262

REVENUE RECOGNITION - Changes t

REVENUE RECOGNITION - Changes to deferred revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
REVENUE RECOGNITION
Beginning balance	$ 279,136	$ 249,010	$ 222,262
Additional amounts deferred	585,971	521,750	452,296
Revenues recognized	(572,387)	(491,624)	(425,548)
Ending balance	$ 292,720	$ 279,136	$ 249,010

REVENUE RECOGNITION - Deferre_2

REVENUE RECOGNITION - Deferred revenue, recognized (Details) $ in Thousands	Dec. 31, 2023 USD ($)
REVENUE RECOGNITION
2024	$ 290,143
2025	2,498
2026	79
Total	$ 292,720

REVENUE RECOGNITION - Contract

REVENUE RECOGNITION - Contract cost balances (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Deferred commissions:
Beginning balance	$ 15,463	$ 12,555	$ 11,743
Additions	16,552	13,913	10,018
Amortization	(10,778)	(11,005)	(9,206)
Ending balance	$ 21,237	15,463	12,555
Contract costs, amortization period	3 years
Impairment loss	$ 0	$ 0	$ 0

BUSINESS COMBINATIONS (Details)

BUSINESS COMBINATIONS (Details)					1 Months Ended	12 Months Ended
	Sep. 22, 2021 USD ($) installment	Aug. 19, 2021 USD ($)	May 12, 2021 USD ($)	Jan. 25, 2021 USD ($) item	Jan. 31, 2021 USD ($) payment	Dec. 31, 2023 USD ($) segment	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Business combinations
Payments For Purchase Commitment Liability						$ 6,424,000	$ 423,000	$ 10,822,000
Number of Operating Segments | segment						1
Increase in settlement value						$ 4,020,000	990,000
Deferred purchase consideration, current							19,824,000
Cash consideration, net							474,000	251,412,000
Other operating expense (income), net
Business combinations
Total transaction cost						4,853,000
LCR
Business combinations
Purchase commitment liability payment	$ 60,038,000
Purchase price	99,062,000
Cash received in the acquisition	1,899,000
Cash paid for Post-closing adjustment	474,000
Aggregate deferred payments	$ 40,000,000
No of Installment of deferred payment | installment	4
Amount per installment of deferred payment	$ 10,000,000
Amount of discount of deferred payments	976,000
Other adjustments	156,000
Fair value of deferred payment, net of discount	$ 39,024,000					0	19,824,000
Interest acquired (as a percent)	100%
Cash consideration, net	$ 57,821,000
Measurement Period Adjustments, Capitalized Software	7,700,000
Measurement Period Adjustments, Other Intangibles	6,500,000
Measurement Period Adjustments, Goodwill	11,178,000
Royalties payable written off	252,000
Tellutax
Business combinations
Purchase commitment liability payment				$ 6,100,000
Contingent consideration				$ 2,200,000
Number of potential earnout payments				3	3
Revenue achievement period				30 months	30 months
Maximum limit on earnout payments				$ 0	$ 0
Earn out payment for applicable measurement period				0	$ 0
Tellutax Contingent Consideration				$ 2,200,000		$ 4,900,000	4,800,000
Tellutax | Revenue discount rate
Business combinations
Value of input used to measure capitalized software				28.5
Tellutax | Estimated linear obsolescence factor
Business combinations
Value of input used to measure capitalized software				20
Taxamo
Business combinations
Purchase commitment liability payment			$ 190,153,000
Fair value of acquisition holdbacks			502,000
Fair value of purchase commitment liability		$ 10,034,000	10,034,000
Purchase price			200,689,000
Payments For Purchase Commitment Liability			10,034,000
Number of Operating Segments | segment						1
Cash received in the acquisition			2,662,000
Restricted cash acquired from acquisition			$ 221,000
Holdback							$ 468,000
Percentage of remaining outstanding share of the acquiree		5%
Interest acquired (as a percent)		100%	95%
Additional equity interests acquired			5%
Cash consideration, net			$ 187,491,000
Taxamo | Other operating expense (income), net
Business combinations
Transaction costs								$ 4,269,000
Systax - VIE
Business combinations
Purchase commitment liability payment	$ 59,720,000

BUSINESS COMBINATIONS - Net ass

BUSINESS COMBINATIONS - Net assets and liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Sep. 22, 2021	May 12, 2021	Jan. 25, 2021
Business combinations
Goodwill	$ 257,842	$ 251,842	$ 270,041
LCR
Business combinations
Cash and cash equivalents				$ 1,899
Accounts receivable				1,586
Prepaid expenses and other current assets				150
Property and equipment				4
Capitalized software				7,700
Goodwill				86,639
Other intangibles				6,500
Accounts payable				(19)
Accrued expenses				(202)
Accrued compensation				(1,746)
Deferred income tax liability				(3,630)
Deferred revenue				(71)
Total				$ 98,810
Taxamo
Business combinations
Cash and cash equivalents					$ 2,441
Funds held for customers					221
Accounts receivable					2,657
Prepaid expenses and other current assets					908
Property and equipment					40,792
Holdback		$ 468
Goodwill					164,199
Other intangibles					1,581
Accounts payable					(304)
Accrued expenses					(1,395)
Accrued compensation					(3,939)
Deferred revenue					(2,196)
Deferred other liabilities					(4,276)
Total					$ 200,689
Tellutax
Business combinations
Capitalized software						$ 3,600
Goodwill						4,700
Other intangibles						$ 8,300

BUSINESS COMBINATIONS - Assumpt

BUSINESS COMBINATIONS - Assumptions of intangible assets acquired in the acquisition (Details) - USD ($) $ in Thousands			12 Months Ended
	Sep. 22, 2021	May 12, 2021	Dec. 31, 2022
Developed technology
Business combinations
Fair Value			$ 40,746
LCR | Trade Name | Goodwill and other intangible assets
Business combinations
Fair Value	$ 200
Estimated Useful Life	6 months
Discount Rate	20%
LCR | Customer relationships | Goodwill and other intangible assets
Business combinations
Fair Value	$ 6,300
Estimated Useful Life	3 years
Discount Rate	20%
LCR | Developed technology | Property and Equipment, net
Business combinations
Fair Value	$ 7,700
Estimated Useful Life	3 years
Discount Rate	20%
Taxamo | Trade Name | Goodwill and other intangible assets
Business combinations
Fair Value		$ 608
Estimated Useful Life		2 years
Discount Rate		16.50%
Taxamo | Customer relationships | Goodwill and other intangible assets
Business combinations
Fair Value		$ 973
Estimated Useful Life		2 years
Discount Rate		16.50%
Taxamo | Developed technology | Property and Equipment, net
Business combinations
Fair Value		$ 40,746
Estimated Useful Life		3 years
Discount Rate		16.50%

INVESTMENTS - Narrative (Detail

INVESTMENTS - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
INVESTMENTS
Accrued interest receivable	$ 20	$ 24

INVESTMENTS - Amortized cost, g

INVESTMENTS - Amortized cost, gross unrealized gains and losses, allowance for credit losses, and fair value (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Investment securities available for sale:
Amortized Cost	$ 10,797	$ 14,911
Gross Unrealized Loss	(8)	(48)
Fair Value	10,789	14,863
Commercial paper
Investment securities available for sale:
Amortized Cost	7,169	9,662
Gross Unrealized Loss	(1)	(2)
Fair Value	7,168	9,660
U.S. Treasury securities
Investment securities available for sale:
Amortized Cost	3,628	5,249
Gross Unrealized Loss	(7)	(46)
Fair Value	$ 3,621	$ 5,203

INVESTMENTS - Gross Unrealized

INVESTMENTS - Gross Unrealized Loss Position (Details) $ in Thousands	Dec. 31, 2023 USD ($) security	Dec. 31, 2022 USD ($) security
Debt securities, unrealized loss position, accumulated loss
Fair value, less than 12 months maturity	$ 4,472	$ 10,210
Fair value, 12 months or longer maturity	2,043	1,457
Fair value, total	6,515	11,667
Debt securities, unrealized loss position, accumulated loss less than 12 months	(1)	(31)
Debt securities, unrealized loss position, accumulated loss 12 months or more	(7)	(19)
Debt securities, unrealized loss position, accumulated loss	$ (8)	$ (50)
Number of securities | security	41	52
Number of securities immaterial | security	24	39
Allowance For Credit Losses	$ 0	$ 0
Commercial Paper
Debt securities, unrealized loss position, accumulated loss
Fair value, less than 12 months maturity	4,472	6,464
Fair value, total	4,472	6,464
Debt securities, unrealized loss position, accumulated loss less than 12 months	(1)	(4)
Debt securities, unrealized loss position, accumulated loss	(1)	(4)
U.S. Treasury Securities
Debt securities, unrealized loss position, accumulated loss
Fair value, less than 12 months maturity		3,746
Fair value, 12 months or longer maturity	2,043	1,457
Fair value, total	2,043	5,203
Debt securities, unrealized loss position, accumulated loss less than 12 months		(27)
Debt securities, unrealized loss position, accumulated loss 12 months or more	(7)	(19)
Debt securities, unrealized loss position, accumulated loss	$ (7)	$ (46)

INVESTMENTS - Maturities (Detai

INVESTMENTS - Maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Fair value of investment securities available for sale:
Due in 1 Year or Less	$ 8,447
Due > 1 Year through 5 Years	2,342
Total	10,789	$ 14,863
Fair value of amortized cost of investment securities available for sale
Due in 1 Year or Less	8,450
Due > 1 Year through 5 Years	2,347
Total	10,797	14,911
Unaccreted discount	114	139
Unamortized premium	0	0
Commercial paper
Fair value of investment securities available for sale:
Due in 1 Year or Less	7,168
Total	7,168	9,660
Fair value of amortized cost of investment securities available for sale
Total	7,169	9,662
U.S. Treasury securities
Fair value of investment securities available for sale:
Due in 1 Year or Less	1,279
Due > 1 Year through 5 Years	2,342
Total	3,621	5,203
Fair value of amortized cost of investment securities available for sale
Total	$ 3,628	$ 5,249

INVESTMENTS - Securities pledge

INVESTMENTS - Securities pledged (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
INVESTMENTS
Debt securities	$ 2,336	$ 0
Debt securities realized gain (loss)	(4)	0
Securities	0	0
Equity securities net gain (loss)	0	0
Unrealized gain (loss)	$ 0	$ 0

FINANCIAL INSTRUMENTS AND FAI_3

FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS (Details)		1 Months Ended
	Jan. 25, 2021 USD ($) item	Jan. 31, 2021 USD ($) payment	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Fair Value, Recurring
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Forward foreign current contract, asset			$ 849,000	$ 569,000
Significant other observable inputs (Level 2) | Fair Value, Recurring
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Forward foreign current contract, asset			849,000	569,000
Money Market Funds | Fair Value, Recurring
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Assets, Fair Value Disclosure			53,049,000	67,430,000
Money Market Funds | Prices in active markets for identical assets (Level 1) | Fair Value, Recurring
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Assets, Fair Value Disclosure			53,049,000	67,430,000
Commercial Paper | Fair Value, Recurring
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Assets, Fair Value Disclosure			7,168,000	9,660,000
Commercial Paper | Significant other observable inputs (Level 2) | Fair Value, Recurring
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Assets, Fair Value Disclosure			7,168,000	9,660,000
U.S. Treasury Securities | Fair Value, Recurring
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Assets, Fair Value Disclosure			3,621,000	5,203,000
U.S. Treasury Securities | Significant other observable inputs (Level 2) | Fair Value, Recurring
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Assets, Fair Value Disclosure			3,621,000	5,203,000
Tellutax
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Tellutax Contingent Consideration	$ 2,200,000		4,900,000	4,800,000
Number of potential earnout payments	3	3
Revenue achievement period	30 months	30 months
Maximum limit on earnout payments	$ 0	$ 0
Earn out payment for applicable measurement period	$ 0	$ 0
Tellutax | Fair Value, Recurring
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Tellutax Contingent Consideration			4,900,000	4,800,000
Tellutax | Significant unobservable inputs (Level 3) | Fair Value, Recurring
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Tellutax Contingent Consideration			$ 4,900,000	$ 4,800,000

FINANCIAL INSTRUMENTS AND FAI_4

FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS - Estimated fair values of Tellutax contingent consideration (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) Y	Dec. 31, 2022 USD ($) Y	Dec. 31, 2021 USD ($)	Jan. 25, 2021 USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value adjustments to contingent consideration	$ 1,549	$ 2,300	$ 300
Purchase commitment and contingent consideration liabilities, current	11,901	6,149
Purchase commitment and contingent consideration liabilities, net of current portion	2,600	8,412
Tellutax
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Tellutax Contingent Consideration	4,900	4,800		$ 2,200
Fair value adjustments to contingent consideration	1,549	2,300
Purchase commitment and contingent consideration liabilities, current	2,300	1,400
Purchase commitment and contingent consideration liabilities, net of current portion	$ 2,600	$ 3,400
Tellutax | Revenue volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration measurement input	60	75
Tellutax | Revenue discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration measurement input	20.8	22.4
Tellutax | Term (in years)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration measurement input | Y	1.3	2.4

FINANCIAL INSTRUMENTS AND FAI_5

FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS - Changes in fair value of Tellutax contingent consideration (Details) - Contingent Consideration - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 4,800	$ 2,500
Acquisition of Tellutax			$ 2,200
Fair value adjustments	1,549	2,300	300
Payments	(1,449)
Ending balance	$ 4,900	$ 4,800	$ 2,500

FINANCIAL INSTRUMENTS AND FAI_6

FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS - Non-recurring Fair Value Measurements (Details) - USD ($) $ in Thousands		12 Months Ended
	Sep. 22, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jan. 07, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred purchase consideration				$ 39,024
Interest expense		$ 4,022	$ 990
LCR
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest acquired (as a percent)	100%
Purchase commitment liability payment	$ 60,038
Deferred purchase consideration		$ 0	19,824
Systax
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest acquired (as a percent)		15%		5%	60%
Purchase commitment liability payment		$ 4,975		$ 788
Total equity interests		80%		65%
Purchase commitment liability			5,012
Purchase commitment liability					$ 12,592
Minimum Purchase Commitment liability		$ 9,601	$ 4,749

PROPERTY AND EQUIPMENT (Details

PROPERTY AND EQUIPMENT (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021
Property and equipment
Property and equipment	$ 263,648		$ 282,939
Less accumulated depreciation	(162,914)		(181,849)
Property and equipment, net	100,734	$ 99,502	101,090	$ 98,016	$ 98,858	$ 97,586	$ 96,710
Leasehold improvements
Property and equipment
Property and equipment	20,662		20,929
Equipment
Property and equipment
Property and equipment	22,012		39,238
Computer software purchased
Property and equipment
Property and equipment	2,690		11,892
Internal-use software
Property and equipment
Property and equipment	181,732		185,015
Less accumulated depreciation	(121,646)		(119,603)
Property and equipment, net	88,969		83,612
Cloud-Based Customer Solutions
Property and equipment
Property and equipment	142,302		142,980
Internal Systems and Tools
Property and equipment
Property and equipment	39,430		42,035
Furniture and fixtures
Property and equipment
Property and equipment	7,669		7,665
In-process internal-use software
Property and equipment
Property and equipment	$ 28,883		$ 18,200

PROPERTY AND EQUIPMENT - Additi

PROPERTY AND EQUIPMENT - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022
Property and equipment
Finance lease amortization	$ 610	$ 1,082	$ 931
Property and equipment, gross	263,648	282,939
Property and equipment, net of accumulated depreciation	100,734	101,090	96,710	$ 99,502	$ 98,016	$ 98,858	$ 97,586
Accumulated amortization	162,914	181,849
Developed technology
Property and equipment
Depreciation expense	12,325	11,770	8,123
Fair Value		40,746
Excluding internal-use software and finance leases
Property and equipment
Depreciation expense	5,847	6,445	7,425
Assets under finance leases
Property and equipment
Property and equipment, net of accumulated depreciation	297	1,461
Accumulated amortization	190	861
Internal-use software
Property and equipment
Property and equipment, gross	181,732	185,015
Property and equipment, net of accumulated depreciation	88,969	83,612
Accumulated amortization	121,646	119,603
Depreciation expense	34,592	27,682	19,076
Internal Systems and Tools
Property and equipment
Property and equipment, gross	39,430	42,035
Depreciation expense	$ 8,745	$ 4,913	$ 3,322

PROPERTY AND EQUIPMENT - Major

PROPERTY AND EQUIPMENT - Major components of internal-use software (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021
Property and equipment
Property and equipment, gross	$ 263,648		$ 282,939
Less accumulated depreciation	(162,914)		(181,849)
Property and equipment	100,734	$ 99,502	101,090	$ 98,016	$ 98,858	$ 97,586	$ 96,710
Internal-use software
Property and equipment
Property and equipment, gross	181,732		185,015
Less accumulated depreciation	(121,646)		(119,603)
Internal-use software developed, net of accumulated depreciation	60,086		65,412
Property and equipment	88,969		83,612
In-process internal-use software
Property and equipment
Property and equipment, gross	$ 28,883		$ 18,200

PROPERTY AND EQUIPMENT - Amount

PROPERTY AND EQUIPMENT - Amounts included in property and equipment additions related to capitalized internal-use software (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cloud-Based Customer Solutions
Property and equipment
Total	$ 29,496	$ 28,918	$ 19,837
Internal Systems and Tools
Property and equipment
Total	17,751	13,356	9,811
Internal-use software
Property and equipment
Total	$ 47,247	$ 42,274	$ 29,648

PROPERTY AND EQUIPMENT - Capita

PROPERTY AND EQUIPMENT - Capitalized cloud implementation costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
PROPERTY AND EQUIPMENT
Unamortized cloud computing implementation costs, prepaid expenses and other current assets	$ 3,995	$ 1,957
Unamortized cloud computing implementation costs, non-current assets	12,475	$ 12,721
Hosting Arrangement, Service Contract, Implementation Cost, Expense, Amortization	$ 2,570

PROPERTY AND EQUIPMENT - Amorti

PROPERTY AND EQUIPMENT - Amortization expense (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Internal Systems and Tools
Software
2024	$ 8,982
2025	6,787
2026	1,615
2027	621
2028	207
Total	18,212
Cloud-Based Customer Solutions
Software
2024	25,151
2025	12,822
2026	3,901
Total	$ 41,874

CAPITALIZED SOFTWARE (Details)

CAPITALIZED SOFTWARE (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Capitalized software, movement
Capitalized software, net	$ 38,771	$ 39,012
Capitalized software amortization expense	19,213	17,018	$ 12,962
LCR
Capitalized software, movement
Capitalized development costs		7,700
Software
Capitalized software, movement
Capitalized software, gross	115,152	96,577
Less accumulated amortization	(81,410)	(62,197)
Capitalized software, net	33,742	34,380
Capitalized development costs	18,972	14,888	11,660
Software | LCR
Capitalized software, movement
Capitalized software amortization expense		3,208
Amortization expenses on acquisition date			$ 642
In-process internal-use software
Capitalized software, movement
Capitalized software, gross	$ 5,029	$ 4,632

CAPITALIZED SOFTWARE - Amortiza

CAPITALIZED SOFTWARE - Amortization expense (Details) - Software $ in Thousands	Dec. 31, 2023 USD ($)
Future amortization expense:
2024	$ 19,143
2025	10,689
2026	3,880
2027	30
Total	$ 33,742

LEASES (Details)

LEASES (Details)	12 Months Ended
	Dec. 31, 2023
Maximum
Remaining lease term (in years)	5 years

LEASES - Lease Assets and Liabi

LEASES - Lease Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Lease assets:
Operating lease right-of-use assets	$ 14,605	$ 17,187
Finance lease assets	$ 107	$ 600
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Property, Plant and Equipment, Net	Property, Plant and Equipment, Net
Total lease assets	$ 14,712	$ 17,787
Current:
Operating lease liabilities	3,717	4,086
Finance lease liabilities	74	103
Total current lease liabilities	3,791	4,189
Non-current:
Operating lease liabilities, non-current	16,567	20,421
Finance lease liabilities, non-current	51	10
Total non-current lease liabilities	16,618	20,431
Total lease liabilities	$ 20,409	$ 24,620

LEASES - Lease Costs, Weighted

LEASES - Lease Costs, Weighted Average Term and Rates (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Lease Cost, Weighted average term and discount rate:
Operating lease cost	$ 4,019	$ 3,714	$ 4,774
Amortization of lease assets	788	1,275	931
Interest on lease liabilities	8	18	16
Total lease cost	$ 4,815	$ 5,007	$ 5,721
Operating leases, weighted-average remaining lease term (in years)	4 years 8 months 12 days	5 years 8 months 12 days
Finance leases, weighted-average remaining lease term (in years)	2 years 1 month 6 days	6 months
Operating leases, weighted-average discount rate	2.30%	2.30%
Finance leases, weighted-average discount rate	5.60%	2.30%

LEASES - Future Maturity of Lea

LEASES - Future Maturity of Lease Liabilities (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Operating Leases
2024	$ 4,228
2025	4,493
2026	4,565
2027	4,636
2028	3,494
Total lease payments	21,416
Less: Imputed Interest	(1,132)
Present value of lease liabilities	20,284
Finance Leases
2024	75
2025	45
2026	11
Total lease payments	131
Less: Imputed Interest	(6)
Present value of lease liabilities	$ 125

GOODWILL AND OTHER INTANGIBLE_3

GOODWILL AND OTHER INTANGIBLE ASSETS (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Goodwill.	$ 257,842	$ 251,842	$ 270,041
Goodwill and other intangible assets	260,238	257,023
Other intangible assets
Finite-Lived Intangible Assets [Line Items]
Other intangible assets, net	$ 2,396	$ 5,181

GOODWILL AND OTHER INTANGIBLE_4

GOODWILL AND OTHER INTANGIBLE ASSETS - Changes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Balance, January 1	$ 251,842	$ 270,041
Measurement period adjustments		(10,329)
Foreign currency translation adjustments	6,000	(7,870)
Balance, December 31, gross	257,842	251,842
Balance, December 31, net	$ 257,842	$ 251,842

GOODWILL AND OTHER INTANGIBLE_5

GOODWILL AND OTHER INTANGIBLE ASSETS - Intangible Assets - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 10,960	$ 10,667
Accumulated amortization	8,564	5,486
Amortization	2,884	4,013	$ 1,066
Cost of Revenues | Software subscriptions
Finite-Lived Intangible Assets [Line Items]
Amortization	243	234	253
Selling and Marketing Expense
Finite-Lived Intangible Assets [Line Items]
Amortization	2,641	3,779	$ 813
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	8,348	8,225
Accumulated amortization	6,385	3,855
Trademarks and tradenames
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,303	1,240
Accumulated amortization	1,119	887
Developed technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,309	1,202
Accumulated amortization	$ 1,060	$ 744
Other intangible assets
Finite-Lived Intangible Assets [Line Items]
Weighted average amortization period (years)	3 years 6 months	3 years 6 months
Total	$ 2,396	$ 5,181
Other intangible assets | LCR
Finite-Lived Intangible Assets [Line Items]
Amortization		$ 2,825

GOODWILL AND OTHER INTANGIBLE_6

GOODWILL AND OTHER INTANGIBLE ASSETS - Future amortization (Details) - Other intangible assets - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Future amortization expense:
2024	$ 2,110
2025	286
Total	$ 2,396	$ 5,181

GOODWILL AND OTHER INTANGIBLE_7

GOODWILL AND OTHER INTANGIBLE ASSETS - Narratives (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 2,884	$ 4,013	$ 1,066
Other intangible assets | LCR
Finite-Lived Intangible Assets [Line Items]
Fair Value of other intangible assets		6,500
Amortization expense		$ 2,825
Assets fair value disclosure			$ 625

DEBT - Credit Agreement (Detail

DEBT - Credit Agreement (Details) - USD ($) $ in Thousands		12 Months Ended
	Mar. 08, 2022	Dec. 31, 2023	Dec. 31, 2022	Mar. 07, 2022	Mar. 31, 2020
Debt
Write off deferred financing costs	$ 370
Second Amendment
Debt
Payments for deferred financing costs	983
Deferred financing costs	277
Term Loan
Debt
Line of credit, outstanding borrowings		$ 46,875	$ 49,063
Term of debt		5 years
Debt instrument interest rate percentage		6.46%	5.42%
Third Amendment To Credit Agreement
Debt
Deferred financing costs		$ 1,112
Debt instrument covenant, aggregate dividends limitation		$ 2,000
Base rate
Debt
Interest rate		8.50%
SOFR
Debt
Interest rate		6.48%
Long-Term Debt
Debt
Face amount					$ 175,000
Line of Credit
Debt
Line of credit, capacity	200,000			$ 100,000	$ 100,000
Line of credit, outstanding borrowings		$ 0	$ 0
Line of Credit | Second Amendment
Debt
Line of credit, capacity		$ 200,000
New Term Loan.
Debt
Face amount	$ 50,000

DEBT - Indebtness (Details)

DEBT - Indebtness (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current portion of long-term debt
Current portion of long-term debt	$ 2,500	$ 2,188
Debt, net of current portion
Deferred financing costs	(316)	(166)
Total debt, net of current portion	44,059	46,709
Total Debt	46,559	48,897
Term Loan
Current portion of long-term debt
Current portion of long-term debt	2,500	2,188
Debt, net of current portion
Debt, net of current portion	$ 44,375	$ 46,875

DEBT - Maturities (Details)

DEBT - Maturities (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Debt Maturities
2024	$ 2,500
2025	2,500
2026	3,437
2027	38,438
Total debt, net of financing costs	$ 46,875

STOCKHOLDERS EQUITY (Details)

STOCKHOLDERS EQUITY (Details) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Mar. 15, 2022
ESPP
Common Stock
Auto exercised options in connection with offering shares issued		207	128
Class A
Common Stock
Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation			3
Class A | Selling stockholders
Common Stock
Auto exercised options in connection with offering shares issued	2,468	800	2,157
Shares exchanged in lieu	314	91	706
Class A | Restricted Stock Units
Common Stock
Shares issued upon vesting of Restricted Stock Units, net (in shares)		48	12
Auto exercised options in connection with offering shares issued	511
Shares exchanged in lieu	285	20
Class A | Restricted Stock Awards
Common Stock
Shares issued upon vesting of Restricted Stock Units, net (in shares)	198	173	352
Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation			11
Shares exchanged in lieu	7	15
Class A | ESPP
Common Stock
Auto exercised options in connection with offering shares issued	152
Class B
Common Stock
Exchange of shares	7,646	6,500	13,310
S Corporation
Common Stock
Amount of estimated dividends liability			$ 2,733	$ 536

EARNINGS PER SHARE (Details)

EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Numerator:
Net Income (Loss)	$ (13,093)	$ (12,304)	$ (1,479)
Class A
Numerator:
Common stock as a percentage of total shares outstanding, basic	36.06%	30.65%	24.12%
Net loss attributable to stockholders, basic	$ (4,721)	$ (3,771)	$ (357)
Common stock as a percentage of total shares outstanding, diluted	36.06%	30.65%	24.12%
Net loss attributable to stockholders, diluted	$ (4,721)	$ (3,771)	$ (357)
Denominator:
Weighted average common stock, basic (in shares)	54,753	45,864	35,647
Weighted average common stock, diluted (in shares)	54,753	45,864	35,647
Net loss per share, basic (in dollars per share)	$ (0.09)	$ (0.08)	$ (0.01)
Net loss per share, diluted (in dollars per share)	$ (0.09)	$ (0.08)	$ (0.01)
Class A | Amended Options
Denominator:
Anti-dilutive shares	7,374	8,982	10,422
Class A | Out-of-the-money options
Denominator:
Anti-dilutive shares	482	760	294
Class A | Restricted Stock Awards
Denominator:
Anti-dilutive shares	168	285	490
Class A | Restricted Stock Units
Denominator:
Anti-dilutive shares	3,910	2,254	387
Class A | ESPP
Denominator:
Anti-dilutive shares	42	52	29
Class B
Numerator:
Common stock as a percentage of total shares outstanding, basic	63.94%	69.35%	75.88%
Net loss attributable to stockholders, basic	$ (8,372)	$ (8,533)	$ (1,122)
Common stock as a percentage of total shares outstanding, diluted	63.94%	69.35%	75.88%
Net loss attributable to stockholders, diluted	$ (8,372)	$ (8,533)	$ (1,122)
Denominator:
Weighted average common stock, basic (in shares)	97,106	103,781	112,133
Weighted average common stock, diluted (in shares)	97,106	103,781	112,133
Net loss per share, basic (in dollars per share)	$ (0.09)	$ (0.08)	$ (0.01)
Net loss per share, diluted (in dollars per share)	$ (0.09)	$ (0.08)	$ (0.01)

EMPLOYEE BENEFIT AND DEFERRED_3

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Compensation plans:
Accrued salaries and benefits	$ 12,277	$ 10,790
ESPP
Compensation plans:
ESPP offering period	6 months
Accrued salaries and benefits	$ 371	$ 311

EMPLOYEE BENEFIT AND DEFERRED_4

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - 401K Plan (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 01, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Compensation plans:
Contribution (as a percent)				3%
401(k) matching contributions		$ 11,285	$ 10,056	$ 4,062
Discretionary profit-sharing
Compensation plans:
Contribution (as a percent)	6%			3%
401(k) discretionary contributions				$ 3,994

EMPLOYEE BENEFIT AND DEFERRED_5

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - Long-Term Rewards Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Compensation plans:
Performance period (in years)	three-year
Deferred compensation, current		$ 2,809
Long-Term Rewards Plan
Compensation plans:
Compensation expense	$ 0	892	$ 3,059
Deferred compensation, current	$ 2,237	$ 4,023

EMPLOYEE BENEFIT AND DEFERRED_6

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - Options under 2020 Plan (Details) - Employee Stock Option [Member] - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Units
Beginning, balance	8,508
Granted	779
Exercised	(2,782)
Forfeited	(34)
Ending balance	5,692	8,508
Exercisable	4,289
Weighted Average Per Share
Beginning balance	$ 4.34
Forfeited	5.82
Exercised	2.32
Ending Balance	5.32	$ 4.34
Exercisable	$ 4.31
Remaining contractual life, outstanding	4 years 8 months 12 days	4 years 3 months 18 days
Remaining contractual life, exercisable	4 years 1 month 6 days
Intrinsic value, outstanding	$ 124,327	$ 86,514
Intrinsic value, exercisable	$ 97,737
Vesting period	10 years
Unrecognized compensation expense	$ 4,756
Unrecognized compensation expense period	1 year 2 months 12 days
Minimum
Weighted Average Per Share
Vesting period	1 year
Maximum
Weighted Average Per Share
Vesting period	4 years

EMPLOYEE BENEFIT AND DEFERRED_7

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - Options under 2020 Plan Price Range (Details) shares in Thousands	12 Months Ended
	Dec. 31, 2023 $ / shares shares
Options outstanding, vested and exercisable:
Options outstanding	5,692
Options vested and exercisable	4,289
$0.15 to $0.71
Options outstanding, vested and exercisable:
Exercise prices, lower range | $ / shares	$ 0.15
Exercise prices, upper range | $ / shares	$ 0.71
Options outstanding	786
$2.15
Options outstanding, vested and exercisable:
Exercise prices | $ / shares	$ 2.15
Options outstanding	147
Options outstanding, life	1 year 1 month 6 days
Options vested and exercisable	147
Options vested and exercisable, life	1 year 1 month 6 days
$2.50
Options outstanding, vested and exercisable:
Exercise prices | $ / shares	$ 2.50
Options outstanding	1,721
Options outstanding, life	2 years 8 months 12 days
Options vested and exercisable	1,721
Options vested and exercisable, life	2 years 8 months 12 days
$2.67
Options outstanding, vested and exercisable:
Exercise prices | $ / shares	$ 2.67
Options outstanding	63
Options outstanding, life	3 years 1 month 6 days
Options vested and exercisable	63
Options vested and exercisable, life	3 years 1 month 6 days
$3.17
Options outstanding, vested and exercisable:
Exercise prices | $ / shares	$ 3.17
Options outstanding	431
Options outstanding, life	4 years 4 months 24 days
Options vested and exercisable	431
Options vested and exercisable, life	4 years 4 months 24 days
$3.73
Options outstanding, vested and exercisable:
Exercise prices | $ / shares	$ 3.73
Options outstanding	1,236
Options outstanding, life	5 years 9 months 18 days
Options vested and exercisable	490
Options vested and exercisable, life	5 years 9 months 18 days
$4.70
Options outstanding, vested and exercisable:
Exercise prices | $ / shares	$ 4.70
Options outstanding	603
Options outstanding, life	6 years 1 month 6 days
Options vested and exercisable	261
Options vested and exercisable, life	6 years 1 month 6 days
$18.47
Options outstanding, vested and exercisable:
Exercise prices | $ / shares	$ 18.47
Options outstanding	213
Options outstanding, life	7 years 10 months 24 days
Options vested and exercisable	107
Options vested and exercisable, life	7 years 10 months 24 days
$18.96
Options outstanding, vested and exercisable:
Exercise prices | $ / shares	$ 18.96
Options outstanding	185
Options outstanding, life	7 years 7 months 6 days
Options vested and exercisable	120
Options vested and exercisable, life	7 years 7 months 6 days
$19.00
Options outstanding, vested and exercisable:
Exercise prices | $ / shares	$ 19
Options outstanding	65
Options outstanding, life	7 years 8 months 12 days
Options vested and exercisable	32
Options vested and exercisable, life	7 years 8 months 12 days
$32.16
Options outstanding, vested and exercisable:
Exercise prices | $ / shares	$ 32.16
Options outstanding	242
Options outstanding, life	7 years 2 months 12 days
Options vested and exercisable	131
Options vested and exercisable, life	7 years 2 months 12 days

EMPLOYEE BENEFIT AND DEFERRED_8

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - 2020 Plan (Details) - Employee Stock Option [Member] shares in Thousands	12 Months Ended
	Dec. 31, 2023 shares
Compensation plans:
Shares authorized	16,500
Available for issuance	15,676
Maximum issuance (as a percentage of outstanding)	4%
Maximum issuance (in shares)	3,000

EMPLOYEE BENEFIT AND DEFERRED_9

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - Options under 2020 Plan Options issued (Details) - $ / shares	3 Months Ended				9 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022
EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS
Fair market value of common stock	$ 18.47	$ 19	$ 17.66	$ 32.16	$ 18.96
Volatility	37.40%	37.10%	36.80%	36.80%	37.10%
Expected term (in years)	5 years	5 years	6 years	6 years	5 years
Risk-free interest rate	1.30%	0.90%	0.40%	0.40%	0.80%

EMPLOYEE BENEFIT AND DEFERRE_10

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - Retired SAR Plan (Details) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended	12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Compensation plans:
Deferred compensation, current							$ 2,809
Stock-based compensation expense						$ 32,714	19,531	$ 25,458
Stock-based compensation expense						$ 33,919	$ 19,729	$ 26,160
Fair Value Assumptions and Methodology
Volatility	37.40%	37.10%	36.80%	36.80%	37.10%
Expected term (in years)	5 years	5 years	6 years	6 years	5 years
Risk-free interest rate	1.30%	0.90%	0.40%	0.40%	0.80%

EMPLOYEE BENEFIT AND DEFERRE_11

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - Restricted Stock Units (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		12 Months Ended
	May 12, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Compensation plans:
Compensation expense		$ 33,919	$ 19,729	$ 26,160
Taxamo
Compensation plans:
Purchase price	$ 200,689
Restricted Stock Units
Compensation plans:
Compensation expense		24,257	$ 9,286	$ 2,964
Unrecognized compensation cost		$ 46,180
Unrecognized compensation expense period		2 years 7 months 6 days
Units
Beginning balance (in units)		2,562
Granted (in units)		2,627
Vested (in units)		(796)
Forfeited (in units)		(222)
Ending balance (in units)		4,171	2,562
Weighted Average Per Share
Beginning balance (in dollars per share)		$ 15.90
Granted (in dollars per share)		16.64
Vested (in dollars per share)		17.45
Forfeited (in dollars per share)		15.23
Ending balance (in dollars per share)		$ 16.11	$ 15.90
Restricted Stock Units | Minimum
Compensation plans:
Service requirement (in years)		1 year
Restricted Stock Units | Maximum
Compensation plans:
Service requirement (in years)		4 years

EMPLOYEE BENEFIT AND DEFERRE_12

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - Restricted Stock Awards (Details) - Restricted Stock Awards $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) $ / shares shares
Units
Beginning balance (in units) | shares	235
Granted (in units) | shares	62
Vested (in units) | shares	(206)
Ending balance (in units) | shares	91
Weighted Average Per Share
Beginning balance (in dollars per share) | $ / shares	$ 14.91
Granted (in dollars per share) | $ / shares	22.69
Vested (in dollars per share) | $ / shares	14.32
Ending balance (in dollars per share) | $ / shares	$ 21.50
Unrecognized compensation cost | $	$ 949
Unrecognized compensation expense period	6 months
Minimum
Compensation plans:
Service requirement (in years)	1 year
Maximum
Compensation plans:
Service requirement (in years)	4 years

EMPLOYEE BENEFIT AND DEFERRE_13

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - Employee Stock Purchase Plan (Details) - ESPP - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2022
Compensation plans:
Purchase price as a percent of fair value	85%
Reserved for issuance			1,000
Maximum issuance (as a percentage of outstanding)		1%
Maximum issuance (in shares)		16,000
Shares available for issuance	4,914
Unrecognized compensation cost	$ 375			$ 324
ESPP offering period	6 months
Discount	15%

EMPLOYEE BENEFIT AND DEFERRE_14

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - ESPP - Option-pricing model key input assumptions (Details) - $ / shares						3 Months Ended				9 Months Ended
	May 31, 2024	Nov. 30, 2023	May 31, 2023	Nov. 30, 2022	May 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022
Fair Value Assumptions and Methodology
Fair market value of common stock						$ 18.47	$ 19	$ 17.66	$ 32.16	$ 18.96
Volatility						37.40%	37.10%	36.80%	36.80%	37.10%
Expected term (in years)						5 years	5 years	6 years	6 years	5 years
Risk-free interest rate						1.30%	0.90%	0.40%	0.40%	0.80%
Initial Public Offering | ESPP
Fair Value Assumptions and Methodology
Fair market value of common stock	$ 27.82	$ 21.76	$ 17.21	$ 11.16	$ 17.38
Volatility	36.60%	39.40%	46.40%	35.40%	37.30%
Expected term (in years)	6 months	6 months	6 months	6 months	6 months
Risk-free interest rate	5.30%	5.40%	4.70%	1.60%	0.10%

EMPLOYEE BENEFIT AND DEFERRE_15

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - Stock based compensation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Allocation of costs
Compensation expense	$ 33,919	$ 19,729	$ 26,160
Employee Stock Option [Member]
Allocation of costs
Compensation expense	6,349	7,081	17,533
Restricted Stock Units
Allocation of costs
Compensation expense	24,257	9,286	2,964
Restricted Stock Awards
Allocation of costs
Compensation expense	2,496	2,768	5,126
ESPP
Allocation of costs
Compensation expense	$ 817	$ 594	$ 537

EMPLOYEE BENEFIT AND DEFERRE_16

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - Stock based compensation, comprehensive loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Allocation of costs
Compensation expense	$ 33,919	$ 19,729	$ 26,160
Recognized tax benefit related to the stock-based compensation expense	16,541	3,324	14,683
Tax benefit from stock options	13,079	2,710	14,159
Software subscriptions
Allocation of costs
Compensation expense	2,834	2,090	2,336
Services
Allocation of costs
Compensation expense	1,846	1,433	2,648
Research and development
Allocation of costs
Compensation expense	5,994	1,798	2,620
Selling and marketing
Allocation of costs
Compensation expense	8,380	6,284	6,371
General and administrative
Allocation of costs
Compensation expense	$ 14,865	$ 8,124	$ 12,185

RELATED PARTIES (Details)

RELATED PARTIES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
RELATED PARTIES
Offering costs related to sale of shares	$ 0	$ 688

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Purchase Obligation, Fiscal Year Maturity [Abstract]
2024	$ 10,450
2025	7,452
2026	4,568
2027	3,696
2028	3,075
Total	$ 29,241

INCOME TAXES - (Details)

INCOME TAXES - (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
INCOME TAXES
Effective tax rate (as a percent)	39.60%	(21.50%)	62.30%
U.S. federal statutory income tax rate	21%	21%	21%

INCOME TAXES - Geography (Detai

INCOME TAXES - Geography (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
INCOME TAXES
U.S.	$ (3,126)	$ 5,827	$ 5,608
Foreign	(18,548)	(15,957)	(9,534)
Loss before income taxes	$ (21,674)	$ (10,130)	$ (3,926)

INCOME TAXES - Benefit (Expense

INCOME TAXES - Benefit (Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Current income taxes:
Federal	$ (279)	$ 1,696
State and local	1,568	1,068	$ 155
Foreign	1,347	577	468
Total current	2,636	3,341	623
Deferred income taxes:
Federal	(9,224)	904	(1,849)
State and local	(1,552)	72	(7)
Foreign	(441)	(2,143)	(1,214)
Total deferred	(11,217)	(1,167)	(3,070)
Income tax expense (benefit)	$ (8,581)	$ 2,174	$ (2,447)

INCOME TAXES - Reconciliation (

INCOME TAXES - Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income taxes:
Loss before income taxes	$ (21,674)	$ (10,130)	$ (3,926)
Income tax benefit from translation adjustments and revaluations	27	12
Taxes:
U.S. federal income tax at statutory rate	(4,552)	(2,128)	(825)
State income taxes	289	441	678
Stock-based compensation expense	(6,236)	1,787	(4,550)
Impact of foreign operations	1,463	1,352	954
Transaction costs		176	1,082
U.S. taxation of foreign earnings	(245)	(179)	144
Nondeductible compensation	2,822	485	682
Tax credits	(5,818)	(341)	(488)
Change in valuation allowance	3,386	427	373
Changes in prior year unrecognized tax benefits	451
Other permanent items, net	(141)	154	(497)
Income tax expense (benefit)	$ (8,581)	$ 2,174	$ (2,447)
Tax Rate (Percentage)
U.S. federal statutory income tax rate	21%	21%	21%
State income taxes	(1.30%)	(4.40%)	(17.30%)
Stock-based compensation expense	28.80%	(17.60%)	115.90%
Impact of foreign operations	(6.80%)	(13.30%)	(24.30%)
Transaction costs	0%	(1.70%)	(27.60%)
U.S. taxation of foreign earnings	1.10%	1.80%	(3.70%)
Nondeductible compensation	(13.00%)	(4.80%)	(17.40%)
Tax credits	(26.80%)	(3.40%)	12.40%
Change in valuation allowance	(15.60%)	(4.20%)	(9.50%)
Changes in prior year unrecognized tax benefits	(2.10%)	0%	0%
Other permanent items, net	0.70%	(1.70%)	12.80%
Taxes and effective tax rate	39.60%	(21.50%)	62.30%
Foreign taxing jurisdiction
Tax Rate (Percentage)
Impact of foreign operations	12.50%	12.50%	12.50%

INCOME TAXES - Net deferred tax

INCOME TAXES - Net deferred tax assets (liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Deferred revenue	$ 3,523	$ 2,981
State operating loss carry forwards	2,682	2,831
Federal and foreign loss carry forwards	4,361	11,318
Accrued expenses	2,239	2,238
Accrued compensation	2,339
Deferred and stock-based compensation	19,008	23,634
Operating lease liabilities	5,151	6,272
Tax credits	3,662
Depreciation and amortization	6,417
Other	2,721
Deferred tax assets	52,103	49,274
Valuation allowance	(5,941)	(2,285)
Total deferred tax assets	46,162	46,989
Deferred tax liabilities:
Depreciation and amortization		(9,337)
Prepaid expenses	(1,026)	(1,256)
Right of use asset	(3,428)	(4,325)
Accrued compensation		(1,434)
Other		(115)
Deferred tax liabilities	(4,454)	(16,467)
Classification in the consolidated balance sheets
Deferred income tax asset	41,708	30,938
Net deferred tax asset	41,708	30,522
Deferred income tax asset
Classification in the consolidated balance sheets
Deferred income tax asset	$ 41,708	30,938
Deferred other liabilities
Classification in the consolidated balance sheets
Deferred other liabilities		$ (416)

INCOME TAXES - Carryforwards (D

INCOME TAXES - Carryforwards (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Operating loss carryforwards
Incremental valuation allowances	$ 5,941	$ 2,285
Foreign
Operating loss carryforwards
Operating Loss Carryforwards	27,577
Non operating loss carryforwards	51
U.S. Federal | Research tax credit carryforward
Operating loss carryforwards
Tax credit carryforward, amount	4,014
State and local
Operating loss carryforwards
Operating Loss Carryforwards	42,090
Incremental valuation allowances
Operating loss carryforwards
Incremental valuation allowances	$ 3,656

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pay vs Performance Disclosure
Net Income (Loss)	$ (13,093)	$ (12,304)	$ (1,479)

Insider Trading Arrangements

Insider Trading Arrangements	12 Months Ended
	Dec. 31, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false