Vertex (VERX) 10-K 16 Mar 22 2021 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2021	Mar. 11, 2022	Jun. 30, 2021
Document Information:
Document Type	10-K
Document Period End Date	Dec. 31, 2021
Document Annual Report	true
Document Transition Report	false
Entity File Number	333-239644
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	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Public Float			$ 485,844,845
Entity Central Index Key	0001806837
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
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		42,338,423
Class B
Document Information:
Entity Common Stock, Shares Outstanding		106,807,000

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 73,333	$ 303,051
Funds held for customers	24,873	9,222
Accounts receivable, net of allowance of $9,151 and $8,592, respectively	76,929	77,159
Prepaid expenses and other current assets	20,536	13,259
Total current assets	195,671	402,691
Property and equipment, net of accumulated depreciation	98,390	56,557
Capitalized software, net of accumulated amortization	33,442	31,989
Goodwill and other intangible assets	272,702	18,711
Deferred commissions	12,555	11,743
Deferred income tax asset	35,298	33,830
Operating lease right-of-use assets	20,249
Other assets	1,900	3,263
Total assets	670,207	558,784
Current liabilities:
Accounts payable	13,000	8,876
Accrued expenses	22,966	19,176
Tax sharing agreement distributions payable	536	2,700
Customer funds obligations	23,461	9,235
Accrued salaries and benefits	16,671	17,326
Accrued variable compensation	26,462	22,372
Deferred compensation, current	4,202	2,057
Deferred revenue	237,344	207,560
Current portion of capital lease obligations		882
Current portion of operating lease liabilities	3,933
Current portion of finance lease liabilities	284
Deferred rent and other		939
Deferred purchase consideration, current	19,805
Purchase commitment and contingent consideration liabilities, current	468	845
Total current liabilities	369,132	291,968
Deferred compensation, net of current portion	1,963	5,010
Deferred revenue, net of current portion	11,666	14,702
Operating lease liabilities, net of current portion	24,320
Finance lease liabilities, net of current portion	68
Capital lease obligations, net of current portion		225
Deferred purchase consideration, net of current portion	19,419
Purchase commitment and contingent consideration liabilities, net of current portion	10,829	8,905
Deferred other liabilities	2,726	8,632
Total liabilities	440,123	329,442
Commitments and contingencies (Note 14)
Stockholders' equity:
Preferred shares, $0.001 par value, 30,000 shares authorized; no shares issued and outstanding
Additional paid in capital	222,621	206,541
Retained earnings	24,811	25,782
Accumulated other comprehensive loss	(17,497)	(3,127)
Total stockholders' equity	230,084	229,342
Total liabilities and stockholders' equity	670,207	558,784
Class A
Stockholders' equity:
Common stock, value issued	42	26
Class B
Stockholders' equity:
Common stock, value issued	$ 107	$ 120

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Allowance for accounts receivable	$ 9,151	$ 8,592
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	300,000
Common stock, shares issued (in shares)	42,286	26,327
Common stock, shares outstanding (in shares)	42,286	26,327
Class B
Common stock par value (per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	150,000	150,000
Common stock, shares issued (in shares)	106,807	120,117
Common stock, shares outstanding (in shares)	106,807	120,117

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues:
Revenues	$ 425,548	$ 374,665	$ 321,500
Cost of revenues:
Cost of revenues	161,892	165,387	110,378
Gross profit	263,656	209,278	211,122
Operating expenses:
Research and development	44,018	54,340	30,557
Selling and marketing	99,005	99,418	68,127
General and administrative	107,009	149,057	71,014
Depreciation and amortization	11,678	11,018	8,996
Other operating expense, net	4,888	203	573
Total operating expenses	266,598	314,036	179,267
(Loss) income from operations	(2,942)	(104,758)	31,855
Interest expense, net	984	3,111	953
(Loss) income before income taxes	(3,926)	(107,869)	30,902
Income tax benefit	(2,447)	(32,788)	(155)
Net income (loss)	(1,479)	(75,081)	31,057
Other comprehensive loss (income) from foreign currency translation adjustments and revaluations, net of tax	14,370	2,636	(5)
Total comprehensive (loss) income	(15,849)	(77,717)	31,062
Software subscriptions
Revenues:
Revenues	358,415	316,763	275,629
Cost of revenues:
Cost of revenues	116,194	105,676	77,259
Services
Revenues:
Revenues	67,133	57,902	45,871
Cost of revenues:
Cost of revenues	45,698	59,711	33,119
Class A
Operating expenses:
Net income (loss) attributable to stockholders, basic	$ (357)	$ (6,335)	$ 23
Net income (loss) per share, basic (in dollars per share)	$ (0.01)	$ (0.57)	$ 0.20
Weighted average common stock, basic (in shares)	35,647	11,096	118
Net income (loss) attributable to stockholders, diluted	$ (357)	$ (6,335)	$ 965
Net income (loss) per share, diluted (in dollars per share)	$ (0.01)	$ (0.57)	$ 0.25
Weighted average common stock, diluted (in shares)	35,647	11,096	3,861
Class B
Operating expenses:
Net income (loss) attributable to stockholders, basic	$ (1,122)	$ (68,746)	$ 31,034
Net income (loss) per share, basic (in dollars per share)	$ (0.01)	$ (0.57)	$ 0.26
Weighted average common stock, basic (in shares)	112,133	120,415	120,417
Net income (loss) attributable to stockholders, diluted	$ (1,122)	$ (68,746)	$ 30,092
Net income (loss) per share, diluted (in dollars per share)	$ (0.01)	$ (0.57)	$ 0.25
Weighted average common stock, diluted (in shares)	112,133	120,415	120,417

Consolidated Statements of Chan

Consolidated Statements of Changes in Equity (Deficit) - USD ($) shares in Thousands, $ in Thousands	Common StockFormer Class A	Common StockFormer Class B	Common StockClass A	Common StockClass B	Additional paid in capital.	Retained Earnings (Accumulated Deficit).ASC 842	Retained Earnings (Accumulated Deficit).	Accumulated Other Comprehensive Loss	Treasury stock	Former Class A	Former Class B	Class A	Class B	Options for redeemable shares	ASC 842	Total
Balance at Dec. 31, 2018		$ 54					$ (88,038)	$ (496)	$ (37,797)							$ (126,277)
Balance (in shares) at Dec. 31, 2018	147	120,270							41,685
Options for redeemable shares, bgn at Dec. 31, 2018														$ 14,581
Remeasurement of options for redeemable shares							(2,763)							2,763		(2,763)
Exercise of stock options, net							(100)									(100)
Exercise of stock options, net (in shares)		225
Purchase of treasury stock									$ (841)							(841)
Purchase of treasury stock (in shares)		(225)							225
Distributions declared							(30,857)									(30,857)
Foreign currency translation adjustments and revaluations								5								5
Net income (loss)							31,057									31,057
Balance at Dec. 31, 2019		$ 54					(90,701)	(491)	$ (38,638)							(129,776)
Balance (in shares) at Dec. 31, 2019	147	120,270							41,910	147
Options for redeemable shares, ending at Dec. 31, 2019														17,344
Balance (in shares) at Jun. 30, 2020											120,443
Balance at Dec. 31, 2019		$ 54					(90,701)	(491)	$ (38,638)							(129,776)
Balance (in shares) at Dec. 31, 2019	147	120,270							41,910	147
Options for redeemable shares, bgn at Dec. 31, 2019														17,344
Remeasurement of options for redeemable shares					$ (21,954)		(29,879)							51,833		(51,833)
Reclassification of options for redeemable shares					69,177											69,177
Reclassification of options for temporary shares value														$ (69,177)
Exercise of stock options prior to the Offering							53									53
Exercise of stock options prior to the Offering (in shares)		173
Reclassification of accumulated S Corporation earnings					(354,291)		354,291
Recapitalization prior to Offering		$ (54)		$ 120	(38,704)				$ 38,638
Recapitalization prior to Offering (in shares)	(147)	(120,443)	173	120,417					(41,910)
Reclassification of SAR liability to equity in connection with the Offering					143,519											143,519
Auto-exercised options in connection with Offering			$ 1		(13,809)											(13,808)
Auto-exercised options in connection with Offering (in shares)			564
Shares issued in connection with Offering, net of Offering costs			$ 24		416,778											416,802
Shares issued in connection with Offering, net of Offering costs (shares)			23,812
Exercise of stock options in connection with the Offering					(7,023)											(7,023)
Exercise of stock options in connection with the Offering (in shares)			510
Vested restricted stock issued in connection with Offering					361											361
Vested restricted stock issued in connection with Offering (in shares)			19
Stock-based compensation expense					12,576											12,576
Distributions paid or payable in connection with Tax Sharing Agreement					(2,733)											(2,733)
Class B shares exchanged for Class A shares (in shares)			300	(300)
Exercise of stock options, net			$ 1		1,687											1,688
Exercise of stock options, net (in shares)			890
Shares issued under ESPP					957											957
Shares issued under ESPP (shares)			59
Distributions declared							(132,901)									(132,901)
Foreign currency translation adjustments and revaluations								(2,636)								(2,636)
Net income (loss)							(75,081)									(75,081)
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								26,327	120,117
Stock-based compensation expense					25,458											25,458
Distributions paid or 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)
Exercise of stock options, net			$ 3		(10,611)											(10,608)
Exercise of stock options, net (in shares)			2,157
Shares issued upon vesting of RSU's, net					(78)											(78)
Shares issued upon vesting of RSU's, net (in shares)			12
Shares issued upon vesting of RSA's, net					(213)											(213)
Shares issued upon vesting of RSA's (in shares)			352
Shares issued under ESPP					2,060											2,060
Shares issued under ESPP (shares)			128
Foreign currency translation adjustments and revaluations								(14,370)								(14,370)
Net income (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								42,286	106,807

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net income (loss)	$ (1,479)	$ (75,081)	$ 31,057
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	44,782	32,215	25,190
Provision for subscription cancellations and non-renewals, net of deferred allowance	466	259	1,232
Amortization of deferred financing costs	211	373	266
Write-off of deferred financing costs		1,387
Stock-based compensation expense	26,160	147,904	9,460
Deferred income tax (benefit) provision	(3,116)	(33,499)	(848)
Redemption of Converted SARs		(22,889)
Non-cash operating lease costs	3,825
Other	510	107	43
Changes in operating assets and liabilities:
Accounts receivable	2,962	(6,762)	(10,116)
Prepaid expenses and other current assets	(5,192)	(1,541)	(809)
Deferred commissions	(812)	(547)	(2,366)
Accounts payable	3,847	(1,842)	3,868
Accrued expenses	3,210	4,568	2,539
Accrued and deferred compensation	(3,735)	(632)	5,318
Deferred revenue	24,691	17,557	27,168
Operating lease liabilities	(4,697)
Other	336	(2,034)	496
Net cash provided by operating activities	91,969	59,543	92,498
Cash flows from investing activities:
Acquisition of business, net of cash acquired	(251,412)	(11,570)
Property and equipment additions	(33,386)	(20,955)	(20,339)
Capitalized software additions	(11,660)	(11,850)	(17,221)
Net cash used in investing activities	(296,458)	(44,375)	(37,560)
Cash flows from financing activities:
Net increase in customer funds obligations	14,226	1,681	4,276
Proceeds from line of credit		12,500
Principal payments on line of credit		(12,500)
Proceeds from long-term debt		175,000
Principal payments on long-term debt		(226,251)	(5,566)
Payments for deferred financing costs, net		(2,436)
Proceeds from issuance of shares in connection with Offering		423,024
Payments for Offering costs		(6,222)
Payments for taxes on exercised stock options		(14,813)
Purchase of treasury stock			(841)
Proceeds from purchases of stock under ESPP	2,060	957
Payments for taxes related to net share settlement of stock-based awards	(12,758)
Proceeds from exercise of stock options	1,859	8,808	68
Distributions to stockholders		(146,116)	(28,566)
Distributions under Tax Sharing Agreement	(2,700)
Payments for purchase commitment liabilities	(10,822)
Payments of finance lease liabilities	(964)
Net cash provided by (used in) financing activities	(9,099)	213,632	(30,629)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(479)	(22)	12
Net increase (decrease) in cash, cash equivalents and restricted cash	(214,067)	228,778	24,321
Cash, cash equivalents and restricted cash, beginning of period	312,273	83,495	59,174
Cash, cash equivalents and restricted cash, end of period	$ 98,206	$ 312,273	$ 83,495

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of cash, cash equivalents and restricted cash to the Consolidated Balance Sheets, end of period:
Cash and cash equivalents	$ 73,333	$ 303,051	$ 75,903
Restricted cash-funds held for customers	24,873	9,222	7,592
Total cash, cash equivalents and restricted cash, end of period	$ 98,206	$ 312,273	$ 83,495

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2021
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	Vertex, Inc. and Subsidiaries Notes to Consolidated Financial Statements (Amounts in thousands, except per share data) 1. Nature of Business Vertex, Inc. (“Vertex”) and its consolidated subsidiaries (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 has a 65% controlling equity interest in Systax Sistemas Fiscais LTDA (“Systax”), a provider of Brazilian transaction tax content and software. Systax was determined to be a Variable Interest Entity (“VIE”) and its accounts have been included in the consolidated financial statements from the acquisition date. 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, consolidated statements of comprehensive income (loss), consolidated statements of cash flows, and consolidated statements of changes in stockholders’ equity (deficit) have been revised to correct for certain immaterial errors, as discussed below. During the fourth quarter of 2021, management identified certain immaterial errors impacting previously issued financial statements beginning as of and for the three and nine month periods ended September 30, 2020 and subsequent annual and quarterly reporting periods through September 30, 2021. Specifically, management identified an understatement of the deferred tax benefit and deferred tax assets Management assessed the materiality of this presentation on prior period consolidated financial statements in accordance with the SEC Staff Accounting Bulletin No. 99, “Materiality”, codified in Accounting Standards Codification (“ASC”) Topic 250, Accounting Changes and Error Corrections . Based on this assessment, management concluded that the error correction is not material to any previously presented interim or annual financial statements. In accordance has revised the previously reported financial information in this Annual Report on Form 10-K The consolidated balance sheets have been revised to reflect the correction as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As Reported ​ Revision ​ As Revised September 30, 2020 (unaudited) ​ ​ ​ ​ ​ ​ ​ Deferred income tax asset $ 32,440 ​ $ 3,856 $ 36,296 Total assets ​ ​ 514,934 ​ ​ 3,856 ​ 518,790 Retained earnings ​ ​ 21,696 ​ ​ 3,856 ​ ​ 25,552 Total stockholders' equity ​ ​ 218,561 ​ ​ 3,856 ​ 222,417 Total liabilities and stockholders' equity ​ ​ 514,934 ​ ​ 3,856 ​ 518,790 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ Deferred income tax asset $ 29,974 ​ $ 3,856 $ 33,830 Total assets ​ ​ 554,928 ​ ​ 3,856 ​ 558,784 Retained earnings ​ ​ 21,926 ​ ​ 3,856 ​ ​ 25,782 Total stockholders' equity ​ ​ 225,486 ​ ​ 3,856 ​ 229,342 Total liabilities and stockholders' equity ​ ​ 554,928 ​ ​ 3,856 ​ 558,784 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2021 (unaudited) ​ ​ ​ ​ ​ ​ ​ Deferred income tax asset $ 30,373 ​ $ 3,856 $ 34,229 Total assets ​ ​ 558,337 ​ ​ 3,856 ​ ​ 562,193 Retained earnings ​ ​ 24,722 ​ ​ 3,856 ​ ​ 28,578 Total stockholders' equity ​ ​ 226,576 ​ ​ 3,856 ​ ​ 230,432 Total liabilities and stockholders' equity ​ ​ 558,337 ​ ​ 3,856 ​ ​ 562,193 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, 2021 (unaudited) ​ ​ ​ ​ ​ ​ ​ Deferred income tax asset $ 32,573 ​ $ 3,856 $ 36,429 Total assets ​ ​ 609,529 ​ ​ 3,856 ​ ​ 613,385 Retained earnings ​ ​ 25,530 ​ ​ 3,856 ​ ​ 29,386 Total stockholders' equity ​ ​ 227,844 ​ ​ 3,856 ​ ​ 231,700 Total liabilities and stockholders' equity ​ ​ 609,529 ​ ​ 3,856 ​ ​ 613,385 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2021 (unaudited) ​ ​ ​ ​ ​ ​ ​ Deferred income tax asset $ 32,816 ​ $ 3,856 $ 36,672 Total assets ​ ​ 645,844 ​ ​ 3,856 ​ ​ 649,700 Retained earnings ​ ​ 21,582 ​ ​ 3,856 ​ ​ 25,438 Total stockholders' equity ​ ​ 224,211 ​ ​ 3,856 ​ ​ 228,067 Total liabilities and stockholders' equity ​ ​ 645,844 ​ ​ 3,856 ​ ​ 649,700 ​ The consolidated statements of comprehensive income (loss) have been revised to reflect the correction as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended September 30, 2020 ​ Nine months ended September 30, 2020 (unaudited) As Reported ​ Revision ​ As Revised ​ As Reported ​ Revision ​ As Revised Income tax benefit $ (30,773) ​ $ (3,856) $ (34,629) ​ $ (31,508) ​ $ (3,856) $ (35,364) Net loss ​ ​ (21,028) ​ ​ 3,856 ​ ​ (17,172) ​ ​ (79,167) ​ ​ 3,856 ​ ​ (75,311) Total comprehensive loss ​ ​ (21,266) ​ ​ 3,856 ​ ​ (17,410) ​ ​ (82,679) ​ ​ 3,856 ​ ​ (78,823) Net loss attributable to Class A stockholders, basic ​ ​ (2,751) ​ ​ 505 ​ ​ (2,246) ​ ​ (2,427) ​ ​ 149 ​ ​ (2,278) Net loss per Class A share, basic ​ ​ (0.15) ​ ​ 0.03 ​ ​ (0.12) ​ ​ (0.40) ​ ​ 0.03 ​ ​ (0.37) Net loss attributable to Class A stockholders, diluted ​ ​ (2,751) ​ ​ 505 ​ ​ (2,246) ​ ​ (2,427) ​ ​ 149 ​ ​ (2,278) Net loss per Class A share, diluted ​ ​ (0.15) ​ ​ 0.03 ​ ​ (0.12) ​ ​ (0.40) ​ ​ 0.03 ​ ​ (0.37) Net loss attributable to Class B stockholders, basic ​ ​ (18,277) ​ ​ 3,351 ​ ​ (14,926) ​ ​ (76,740) ​ ​ 3,707 ​ ​ (73,033) Net loss per Class B share, basic ​ ​ (0.15) ​ ​ 0.03 ​ ​ (0.12) ​ ​ (0.64) ​ ​ 0.03 ​ ​ (0.61) Net loss attributable to Class B stockholders, diluted ​ ​ (18,277) ​ ​ 3,351 ​ ​ (14,926) ​ ​ (76,740) ​ ​ 3,707 ​ ​ (73,033) Net loss per Class B share, diluted ​ ​ (0.15) ​ ​ 0.03 ​ ​ (0.12) ​ ​ (0.64) ​ ​ 0.03 ​ ​ (0.61) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As Reported ​ Revision ​ As Revised Income tax benefit ​ ​ ​ ​ ​ ​ ​ ​ ​ $ (28,932) ​ $ (3,856) $ (32,788) Net loss ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (78,937) ​ ​ 3,856 ​ ​ (75,081) Total comprehensive loss ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (81,573) ​ ​ 3,856 ​ ​ (77,717) Net loss attributable to Class A stockholders, basic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (6,660) ​ ​ 325 ​ ​ (6,335) Net loss per Class A share, basic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (0.60) ​ ​ 0.03 ​ ​ (0.57) Net loss attributable to Class A stockholders, diluted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (6,660) ​ ​ 325 ​ ​ (6,335) Net loss per Class A share, diluted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (0.60) ​ ​ 0.03 ​ ​ (0.57) Net loss attributable to Class B stockholders, basic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (72,277) ​ ​ 3,531 ​ ​ (68,746) Net loss per Class B share, basic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (0.60) ​ ​ 0.03 ​ ​ (0.57) Net loss attributable to Class B stockholders, diluted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (72,277) ​ ​ 3,531 ​ ​ (68,746) Net loss per Class B share, diluted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (0.60) ​ ​ 0.03 ​ ​ (0.57) ​ The consolidated statements of cash flows have been revised to reflect the correction as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine months ended September 30, 2020 (unaudited) As Reported ​ Revision ​ As Revised Net loss $ (79,167) ​ $ 3,856 $ (75,311) Deferred income tax benefit ​ ​ (32,004) ​ ​ (3,856) ​ ​ (35,860) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended December 31, 2020 ​ ​ As Reported ​ Revision ​ As Revised Net loss $ (78,937) ​ $ 3,856 $ (75,081) Deferred income tax benefit ​ ​ (29,643) ​ ​ (3,856) ​ ​ (33,499) ​ The consolidated statements of changes in stockholders’ equity (deficit) have been revised to reflect the correction as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended September 30, 2020 (unaudited) ​ As Reported ​ Revision ​ As Revised Net loss ​ $ (21,028) ​ $ 3,856 ​ $ (17,172) Retained earnings ​ ​ 21,696 ​ ​ 3,856 ​ ​ 25,552 Total stockholders' equity ​ ​ 218,561 ​ ​ 3,856 ​ ​ 222,417 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended December 31, 2020 ​ ​ As Reported ​ Revision ​ As Revised Net loss ​ $ (78,937) ​ $ 3,856 ​ $ (75,081) Retained earnings ​ ​ 21,926 ​ ​ 3,856 ​ ​ 25,782 Total stockholders' equity ​ ​ 225,486 ​ ​ 3,856 ​ ​ 229,342 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended March 31, 2021 (unaudited) ​ As Reported ​ Revision ​ As Revised Retained earnings ​ $ 24,722 ​ $ 3,856 ​ $ 28,578 Total stockholders' equity ​ ​ 226,576 ​ ​ 3,856 ​ ​ 230,432 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three and six months ended June 30, 2021 (unaudited) As Reported ​ Revision ​ As Revised Retained earnings ​ $ 25,530 ​ $ 3,856 ​ $ 29,386 Total stockholders' equity ​ ​ 227,844 ​ ​ 3,856 ​ ​ 231,700 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three and nine months ended September 30, 2021 (unaudited) As Reported ​ Revision ​ As Revised Retained earnings ​ $ 21,582 ​ $ 3,856 ​ $ 25,438 Total stockholders' equity ​ ​ 224,211 ​ ​ 3,856 ​ ​ 228,067 ​ Registration of Company Stock and Initial Public Offering On July 28, 2020, the Company filed its amended and restated certificate of incorporation with the Delaware Secretary of State to: (i) effect a three-for-one forward stock split (the “Stock Split”); (ii) establish a new capital structure for the Company (the “New Capital Structure”); and (iii) effect a share exchange (the “Share Exchange”) (collectively, the “Recapitalization”). The Stock Split resulted in each one share owned by a stockholder being exchanged for three The Company’s Registration Statement on Form S-1 with the Securities and Exchange Commission (“SEC”) was declared effective on July 28, 2020, resulting in the Class A shares being registered and available for trading on the NASDAQ exchange (the “Offering”). On July 31, 2020, the Company received $423,024 in proceeds from the sale of 23,812 shares of Class A at a public offering price of $19.00 per share, net of underwriting fees, and used a portion of the proceeds to pay off $175,000 in outstanding debt. The net proceeds remaining after payment of Offering costs are being used for working capital and other corporate purposes. 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, 2021, 2020 and 2019 approximately 7%, 5% and 4%, respectively, of the Company’s revenues were generated outside of the U.S. As of December 31, 2021 and 2020, $699 and $287, 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, 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 subscription cancellations. 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, 2021, 2020 and 2019. 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) the reserve for self-insurance, (iv) assumptions related to achievement of technological feasibility for software developed for sale, (v) product life cycles, (vi) estimated useful lives and potential impairment of long-lived assets and intangible assets, (vii) potential impairment of goodwill, (viii) determination of the fair value of tangible and intangible assets acquired, liabilities assumed and consideration transferred in acquisitions, (ix) amortization period of material rights and deferred commissions (x) valuation of the Company’s stock used to measure stock-based compensation awards, (xi) Black-Scholes-Merton option pricing model (“Black-Scholes model”) input assumptions used to determine the fair value of stock-based compensation awards, (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 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. See Recently Adopted Accounting Pronouncements, Leases ​ ​ 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 Internal-Use Software The Company follows ASC 350-40, Goodwill and Other, Internal-Use Software, 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 future revenues, estimated economic life and changes in technology. Capitalized software includes direct labor and related expenses for software development for new products and enhancements to existing products and acquired software. 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 to five years. Unamortized capitalized software development costs determined to be in excess of the net realizable value of the product are expensed immediately. Capitalized software costs are subject to an ongoing assessment of recoverability based on anticipated future revenues and changes in software technologies at least annually at December 31, and whenever events or circumstances make it more likely than not that impairment may have occurred. 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 income (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 income (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 Accounting Standards Update (“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 On the effective date of the Offering, the Company adopted the 2020 Incentive Award Plan (the “2020 Plan”) and the 2020 Employee Stock Purchase Plan (the “ESPP”), which 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. SARs are accounted for as liabilities under ASC 718 and, as such, the Company recognizes stock-based compensation expense by remeasuring the value of the SARs at the end of each reporting period and accruing the portion of the requisite service rendered at that date. Prior to the date management determined the Company was considered to have become a public entity, the Company measured SARs at their intrinsic value. After such date, management remeasured outstanding SARs using the fair value-based method under ASC 718. Stock-based compensation expense for stock options issued under the 2020 Plan after the Offering 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. A total of 1,000 shares of Class A common were initially reserved for issuance under the ESPP. The number of shares available for issuance under the ESPP will be increased 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 common stock outstanding on the final day of the immediately preceding calendar year and (ii) such smaller number of shares as is determined by the board of directors (“Board”), provided that no more than 16,000 shares of Class A common stock may be issued. The ESPP is administered by a committee of the Board. As of December 31, 2021, there were 2,278 shares available for issuance under the ESPP. The ESPP permits participants to purchase Class A common stock through payroll deductions, up to a specified percentage of their eligible compensation, or for the initial offering period ended November 30, 2020, a lump sum contribution. 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 Effective January 1, 2021, the Company adopted ASU No. 2016-02, Leases 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 income (loss) on a straight-line basis over the lease term. For periods prior to the adoption of ASC 842, the Company recorded rent expense on a straight-line basis over the term of the related lease. The difference between the straight-line rent expense and the payments made in accordance with the operating lease agreements were recognized as a deferred rent liability within other liabilities on the accompanying consolidated balance sheets. 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 $1,922 and $1,766 at December 31, 2021 and 2020, 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 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 (collectively “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. Certain on-premise software subscription prices in the initial subscription year are higher than standard renewal prices. The excess initial year price over the renewal price (“new sale premium”) 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. 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. 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 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. 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 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,

REVENUE RECOGNITION

REVENUE RECOGNITION	12 Months Ended
	Dec. 31, 2021
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, ​ ​ 2021 2020 2019 Software subscriptions: ​ ​ ​ ​ ​ ​ Software licenses ​ $ 231,371 ​ $ 229,744 ​ $ 223,116 Cloud subscriptions ​ ​ 127,044 ​ ​ 87,019 ​ ​ 52,513 Software subscriptions ​ ​ 358,415 ​ ​ 316,763 ​ ​ 275,629 Services ​ 67,133 ​ 57,902 ​ 45,871 Total revenues ​ $ 425,548 ​ $ 374,665 ​ $ 321,500 ​ 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: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Year Ended December 31, ​ 2021 2020 Balance, beginning of period ​ $ 77,159 ​ $ 70,367 Balance, end of period ​ 76,929 ​ 77,159 Increase, net ​ $ (230) ​ $ 6,792 ​ 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 $6,537 and $6,432 at December 31, 2021 and 2020, 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, ​ ​ 2021 ​ 2020 ​ 2019 ​ Balance ​ Net Change Balance ​ Net Change Balance ​ Net Change Allowance balance, January 1 ​ $ (8,592) ​ ​ $ (7,515) ​ ​ $ (5,527) ​ Allowance balance, December 31 ​ (9,151) ​ ​ (8,592) ​ ​ (7,515) ​ Change in allowance ​ ​ ​ $ 559 ​ ​ ​ $ 1,077 ​ ​ ​ $ 1,988 Deferred allowance balance, January 1 ​ 6,432 ​ ​ 5,614 ​ ​ 4,858 ​ Deferred allowance balance, December 31 ​ 6,537 ​ ​ 6,432 ​ ​ 5,614 ​ Change in deferred allowance ​ ​ ​ (105) ​ ​ ​ (818) ​ ​ ​ (756) Net amount charged to revenues ​ ​ ​ $ 454 ​ ​ ​ $ 259 ​ ​ ​ $ 1,232 ​ The amount of revenue recognized during the years ended December 31, 2021, 2020 and 2019 that was included in the opening deferred revenue balance of the same fiscal year was $207,560, $191,745, and $163,939, 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 table provides information about the balances of and changes to deferred revenue for the following periods: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ ​ 2021 ​ 2020 Balances: ​ ​ Deferred revenue, current ​ $ 237,344 ​ $ 207,560 Deferred revenue, non-current ​ 11,666 ​ 14,702 Total deferred revenue ​ $ 249,010 ​ $ 222,262 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Year Ended December 31, ​ ​ 2021 ​ 2020 ​ 2019 Changes to deferred revenue: ​ ​ ​ Beginning balance ​ $ 222,262 ​ $ 205,791 ​ $ 178,703 Additional amounts deferred ​ 452,296 ​ 391,136 ​ 348,588 Revenues recognized ​ (425,548) ​ (374,665) ​ (321,500) Ending balance ​ $ 249,010 ​ $ 222,262 ​ $ 205,791 ​ Deferred revenue at December 31, 2021 will be recognized as follows for all future years: ​ ​ ​ ​ ​ Year Ending December 31, ​ ​ 2022 ​ $ 237,344 2023 ​ 10,161 2024 ​ 1,505 Total ​ $ 249,010 ​ 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 income (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 table provides information about the changes to contract cost balances as of and for the following periods: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Year Ended December 31, ​ ​ 2021 ​ 2020 ​ 2019 Changes to deferred commissions: ​ ​ ​ Beginning balance ​ $ 11,743 ​ $ 11,196 ​ $ 8,830 Additions ​ 10,018 ​ 8,291 ​ 10,140 Amortization ​ (9,206) ​ (7,744) ​ (7,774) Ending balance ​ $ 12,555 ​ $ 11,743 ​ $ 11,196 ​

BUSINESS COMBINATIONS

BUSINESS COMBINATIONS	12 Months Ended
	Dec. 31, 2021
BUSINESS COMBINATIONS
BUSINESS COMBINATIONS	3. LCR-Dixon On September 22, 2021, the Company executed a stock purchase agreement with 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 Company’s accounting for the LCR-Dixon acquisition is preliminary. The preliminary purchase price was $98,744 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 and (ii) 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 (the “deferred purchase consideration”). The purchase price is subject to purchase price adjustments related to the final determination of LCR-Dixon’s cash, net working capital, and taxes as of the acquisition date. Cash consideration was funded from available cash on hand. Management recorded deferred purchase consideration of $39,024, net of a discount of $976 which will be recorded as interest expense over the payment period using the effective interest method. The deferred purchase consideration, net of discount, is included in current liabilities and long-term liabilities at $19,805 and $19,419, respectively, in the consolidated balance sheet at December 31, 2021. The following table summarizes the preliminary purchase price for LCR-Dixon: ​ ​ ​ ​ ​ ​ ​ September 22, 2021 Cash paid at closing ​ $ 59,720 Fair value of deferred purchase consideration ​ ​ 39,024 Total ​ $ 98,744 ​ The preliminary 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 preliminary 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. The Company expects that goodwill associated with the LCR-Dixon acquisition will not be deductible for tax purposes. The preliminary values recorded, which are reflected in the table below, will be adjusted during the Measurement Period as more detailed analyses are performed and further information becomes available regarding the fair values of these amounts on the acquisition date. The Company does not have a preliminary estimate of identifiable intangible assets as of the acquisition date. A third-party expert has been engaged to assist in the valuation of identifiable intangible assets and deferred payments as part of the acquisition. Any subsequent adjustments to the preliminary values not associated with determination of their fair values on the acquisition date will be recorded in the consolidated statements of comprehensive income (loss) in the period in which the adjustment is identified. LCR-Dixon’s business and product offerings are being integrated into the Company’s one operating segment. The following table presents the preliminary 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: ​ ​ ​ ​ ​ ​ ​ September 22, 2021 Cash and cash equivalents ​ $ 1,899 Accounts receivable ​ ​ 1,437 Prepaid expenses and other current assets ​ ​ 326 Property and equipment ​ ​ 4 Goodwill ​ ​ 96,968 Accounts payable ​ ​ (19) Accrued expenses ​ ​ (306) Accrued compensation ​ ​ (1,746) Deferred revenue ​ ​ (71) Total ​ $ 98,492 ​ The Company and LCR-Dixon had a pre-existing relationship in the form of the royalty agreement at the date of acquisition. 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 terminated upon consummation of the acquisition and the Company wrote-off $252 of royalties payable to LCR-Dixon with an offset to goodwill. The Company has included the financial results of LCR-Dixon in the consolidated statement of comprehensive income (loss) from the date of acquisition. The transaction costs associated with the acquisition were not material. 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 is fixed in Euros and approximates $468, which amount is included in purchase commitment and contingent consideration liabilities, current in the consolidated balance sheet as of December 31, 2021. 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 income ​ ​ — 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 5) ​ $ 40,746 ​ Multi-period excess earnings method - income approach ​ 3 years ​ 16.5 % Trade name ​ Goodwill and other intangible assets (Note 8) ​ $ 608 ​ Relief from royalty method - income approach ​ 2 years ​ 16.5 % Customer relationships ​ Goodwill and other intangible assets (Note 8) ​ $ 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. 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. The estimated fair value of the Tellutax Contingent Consideration recorded as of the acquisition date was $2,200. See Note 4 for information on recurring fair value adjustments after the acquisition date. Systax On January 7, 2020, the Company acquired a 60% controlling interest in Systax, a provider of Brazilian transaction tax content and software. Cash consideration for the purchase was $12,374, which was funded through borrowings under a revolving line of credit. This acquisition provided the Company with full access to a sizeable database of Brazilian tax content that is critical to supporting its global multi-national customers’ business expansion into Brazil. On the acquisition date, the Company had a contractual purchase commitment to acquire the remaining 40% equity interest from the original Systax Quotaholders incrementally between 2021 through 2024. This contractual purchase commitment was deemed to be a forward contract, for which the Company was required to estimate and record a future purchase commitment liability (the “Purchase Commitment Liability”). The Purchase Commitment Liability was recorded at the acquisition date fair value of $12,592. Subsequent adjustments will be recorded based on settlement value. This amount will fluctuate as a result of changes in foreign currency exchange rates and is reflected in Purchase Commitment Liability in the consolidated balance sheet at December 31, 2021 and 2020. Adjustments to the settlement 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 acquisition was accounted for as a business combination and the total purchase price was allocated to the assets acquired and liabilities assumed based on their estimated fair values on the acquisition date, with the excess being recorded as goodwill. The fair values of assets acquired and liabilities assumed as of the acquisition date are reflected in the tables below. Any adjustments to these values will be recorded in the consolidated statements of comprehensive income (loss) in the period the change is identified. No such adjustments have been recorded through December 31, 2021. The following table reflects the purchase price for Systax: ​ ​ ​ ​ ​ ​ ​ January 7, 2020 Cash paid to Systax Quotaholders at closing ​ $ 11,626 Cash held in escrow for benefit of Systax Quotaholders ​ 748 Initial cash consideration ​ ​ 12,374 Purchase Commitment Liability ​ 12,592 Total ​ $ 24,966 ​ 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: ​ ​ ​ ​ ​ ​ ​ January 7, 2020 Cash ​ $ 56 Accounts receivable ​ ​ 495 Property and equipment ​ 112 Other current assets ​ 14 Goodwill ​ 21,089 Other intangible assets ​ ​ 3,650 Accounts payable ​ (358) Accrued expenses ​ ​ (92) Total ​ $ 24,966 ​ The excess of the purchase consideration over the net assets acquired is recorded as goodwill and 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. Goodwill is deductible for tax purposes. The Company has included the financial results of Systax in the consolidated statement of comprehensive income (loss) from the date of acquisition in accordance with ASC 810 due to the Company having a controlling financial interest in Systax. The transaction costs associated with the acquisition were $504 and were recorded in general and administrative expense in the year ended December 31, 2019. ​ The Company acquired an additional 5% equity interest of Systax in April 2021 for $788, increasing the Company’s equity interest in Systax to 65%. The Purchase Commitment Liability included in purchase commitment and contingent consideration liabilities, net of current portion in the consolidated balance sheets on December 31, 2021 was $8,329. The Purchase Commitment Liability included in purchase commitment and contingent consideration liabilities, net of current portion in the consolidated balance sheets and purchase commitment and contingent consideration liabilities, current on December 31, 2020 was $8,905 and $845, respectively. ​ 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 current and prior year periods.

FINANCIAL INSTRUMENTS AND FAIR

FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS	12 Months Ended
	Dec. 31, 2021
FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS
FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS	4. Financial instruments and fair value measurements Assets and Liabilities Measured at Fair Value on a Recurring Basis The Company has investments in money market accounts, 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 account fair values are known and observable through daily published floating net asset values. The following table summarizes the Company’s Fair Value Hierarchy for its financial assets and liabilities measured at fair value on a recurring basis: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements Using ​ As of December 31, 2021 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 ​ $ 10,703 ​ $ 10,703 ​ $ — ​ $ — ​ Tellutax Contingent Consideration ​ $ (2,500) ​ $ — ​ $ — ​ $ (2,500) ​ Foreign currency forward contracts ​ $ — ​ $ — ​ $ (62) ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements Using ​ As of December 31, 2020 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 ​ $ 265,270 ​ $ 265,270 ​ $ — ​ $ — ​ Tellutax Contingent Consideration ​ $ — ​ $ — ​ $ — ​ $ — ​ Foreign currency forward contracts ​ $ — ​ $ — ​ $ 448 ​ $ — ​ ​ Tellutax Contingent Consideration The Tellutax acquisition entitles 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. The Tellutax Contingent Consideration fair value is $2,500 at December 31, 2021, which represents an increase from $2,200 as of the acquisition date. Fair value adjustments of $300 were recorded in other operating expense, net for the year ended December 31, 2021. The Tellutax Contingent Consideration fair value of $2,500 is included in purchase commitment and contingent consideration liabilities, net of current portion in the consolidated balance sheet at December 31, 2021. Tellutax Contingent Consideration fair value and unobservable inputs used for the Monte Carlo Simulation valuation were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 Liability Fair Value Valuation Technique Unobservable Inputs Tellutax Contingent Consideration ​ $ (2,500) ​ Monte Carlo Simulation ​ Revenue volatility ​ 95.0 % ​ ​ ​ ​ ​ ​ ​ Revenue discount rate ​ 20.0 % ​ ​ ​ ​ ​ ​ ​ Term (in years) ​ 3.6 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ January 25, 2021 Liability Fair Value Valuation Technique Unobservable Inputs Tellutax Contingent Consideration ​ $ (2,200) ​ Monte Carlo Simulation ​ Revenue volatility ​ 95.0 % ​ ​ ​ ​ ​ ​ ​ Revenue discount rate ​ 20.3 % ​ ​ ​ ​ ​ ​ ​ Term (in years) ​ 4.3 ​ ​ 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) ​ 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 amounts for accounts receivable, accounts payable, and accrued expenses approximate their relative fair values due to their short-term nature and are considered Level 2 measurements. 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. See Note 3. See Note 3 for information on the LCR-Dixon deferred purchase consideration of $39,224 and the Systax Purchase Commitment Liability of $8,329 recorded in the consolidated balance sheet at December 31, 2021. The carrying amounts of both approximated their respective fair values at December 31, 2021 and are considered Level 3 non-recurring fair value measurements. ​ The Company’s obligation with respect to future purchase commitments to the Systax Quotaholders was determined to be a forward contract necessitating initial recognition based on fair value. We estimated the initial fair value of our Purchase Commitment Liability using a Monte Carlo simulation, which we consider 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 We may periodically enter into derivative contracts to reduce our exposure to foreign currency exchange rates. Historically we have not designated derivative contracts as hedges. The derivative contracts are typically designed to manage specific risks according to our strategies, which may change from time to time. In May 2020, we entered into a series of foreign currency forward contracts to reduce our exposure to adverse fluctuations in the Brazilian Real associated with a portion of our Purchase Commitment Liability. Such forward contracts, have not been designated as a hedge, do not qualify for hedge accounting and are not material to our consolidated financial statements. We remeasure these forward contacts at fair value on a recurring basis and include them in other assets in our consolidated balance sheets with changes in their estimated fair value recognized as interest expense in our consolidated statements of comprehensive income or loss. Our fair value determinations are based on foreign currency exchange rates in active markets, which we consider to be Level 2 measurements within the Fair Value Hierarchy.

PROPERTY AND EQUIPMENT

PROPERTY AND EQUIPMENT	12 Months Ended
	Dec. 31, 2021
PROPERTY AND EQUIPMENT
PROPERTY AND EQUIPMENT	5 . The major components of property and equipment are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ ​ 2021 ​ 2020 Leasehold improvements ​ $ 20,956 ​ $ 20,907 Equipment ​ 41,937 ​ 41,410 Computer software purchased ​ 11,792 ​ 11,620 Internal-use software developed: ​ ​ ​ ​ Cloud-based customer solutions ​ 114,872 ​ 65,423 Internal systems and tools ​ 32,408 ​ 25,349 Furniture and fixtures ​ 7,675 ​ 7,674 In-process internal-use software ​ 16,965 ​ 3,304 ​ ​ 246,605 ​ 175,687 Less accumulated depreciation ​ (148,215) ​ (119,130) Property and equipment, net ​ $ 98,390 ​ $ 56,557 ​ Depreciation expense for property and equipment, excluding all internal-use software developed and finance leases, was $7,425, $7,833 and $7,386 for the years ended December 31, 2021, 2020 and 2019, 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 income (loss). Finance lease amortization was $931 for the year ended December 31, 2021. Depreciation expense for assets held under capital leases was $743 and $565 for the years ended December 31, 2020 and 2019, respectively. Finance lease amortization and depreciation expense for assets held under capital leases are included in depreciation and amortization in the consolidated statements of comprehensive income (loss). Assets under finance leases of $1,533, net of accumulated amortization of $931, at December 31, 2021 are included in property and equipment in the consolidated balance sheets. Assets under capital leases of $1,360 and $1,455, net of accumulated depreciation of $1,370 and $627, at December 31, 2020 and 2019, 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, ​ ​ 2021 ​ 2020 Internal-use software developed ​ $ 147,280 ​ $ 90,772 Less accumulated depreciation ​ (87,281) ​ (65,090) ​ ​ 59,999 ​ 25,682 In-process internal-use software ​ 16,965 ​ 3,304 Internal-use software developed, net ​ $ 76,964 ​ $ 28,986 ​ Amounts capitalized for internal-use software developed, excluding acquired technology, and included in property and equipment additions on the consolidated statements of cash flows are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Year Ended December 31, ​ ​ 2021 ​ 2020 ​ 2019 Cloud-based customer solutions $ 19,837 $ 14,710 $ 10,179 Internal systems and tools ​ 11,491 ​ 3,176 ​ 4,860 Total ​ $ 31,328 ​ $ 17,886 ​ $ 15,039 ​ 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, 2021, 2020 and 2019 was $19,076, $8,818 and $7,982, respectively, and is included in cost of revenues, software subscriptions in the consolidated statements of comprehensive income (loss). During the year ended December 31, 2021, 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 sheet at December 31, 2021. Depreciation expense from the acquisition date through December 31, 2021 associated with this developed technology was $8,123 and was reflected in cost of revenues - software subscriptions in the consolidated statement of comprehensive income (loss) for the year ended December 31, 2021. Depreciation expense for internal-use software developed for internal systems and tools for the years ended December 31, 2021, 2020 and 2019 was $3,322, $2,442 and $1,045, respectively, and is included in depreciation and amortization in the consolidated statements of comprehensive income (loss). Amortization expense of internal-use software developed, excluding in-process internal-use software not yet available for its intended use, at December 31, 2021 is as follows for all future years: ​ ​ ​ ​ ​ ​ ​ ​ Year Ending December 31, Internal Systems and Tools Cloud-Based Customer Solutions 2022 ​ $ 3,861 ​ $ 24,740 2023 ​ 2,831 ​ 19,624 2024 ​ 1,988 ​ 5,988 2025 ​ 845 ​ — 2026 ​ 122 ​ — Total ​ $ 9,647 ​ $ 50,352 ​

CAPITALIZED SOFTWARE

CAPITALIZED SOFTWARE	12 Months Ended
	Dec. 31, 2021
CAPITALIZED SOFTWARE
CAPITALIZED SOFTWARE	6. 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, ​ 2021 2020 Capitalized software ​ $ 72,512 ​ $ 63,071 Less accumulated amortization ​ (45,179) ​ (32,217) ​ ​ 27,333 ​ 30,854 In-process capitalized software ​ 6,109 ​ 1,135 Capitalized software, net ​ $ 33,442 ​ $ 31,989 ​ Software development costs capitalized for the years ended December 31, 2021, 2020 and 2019 were $11,660, $11,850 and $17,221, respectively. In-process capitalized software at December 31, 2021 includes the acquisition date fair value of $3,600 for developed technology acquired in the Tellutax acquisition as the Company undertakes necessary enhancements to integrate the technology with the Company’s existing software architecture. Capitalized software amortization expense for the years ended December 31, 2021, 2020 and 2019 was $12,962, $11,936 and $8,212, respectively, and is included in cost of revenues, software subscriptions in the consolidated statements of comprehensive income (loss). In-process capitalized software at December 31, 2021 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, 2021 is as follows for all future years: ​ ​ ​ ​ ​ Year Ending December 31, ​ 2022 ​ $ 11,352 2023 ​ 8,514 2024 ​ 5,802 2025 ​ 1,416 2026 ​ 249 Total ​ $ 27,333 ​

LEASES

LEASES	12 Months Ended
	Dec. 31, 2021
LEASES
LEASES	7. The Company leases office space, IT equipment and office equipment. The Company’s leases have remaining terms of up to 7 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 2021 Lease assets: ​ ​ ​ ​ Operating lease right-of-use assets ​ Operating lease right-of-use assets ​ $ 20,249 Finance lease assets ​ Property and equipment, net (Note 5) ​ ​ 602 Total lease assets ​ ​ ​ $ 20,851 ​ ​ ​ ​ ​ ​ Lease liabilities: ​ ​ ​ ​ ​ Current: ​ ​ ​ ​ ​ Operating lease liabilities ​ Current portion of operating lease liabilities ​ $ 3,933 Finance lease liabilities ​ Current portion of finance lease liabilities ​ ​ 284 Total current lease liabilities ​ ​ ​ ​ 4,217 Non-current: ​ ​ ​ ​ ​ Operating lease liabilities ​ Operating lease liabilities, net of current portion ​ ​ 24,320 Finance lease liabilities ​ Finance lease liabilities, net of current portion ​ ​ 68 Total non-current lease liabilities ​ ​ ​ ​ 24,388 Total lease liabilities ​ ​ ​ $ 28,605 ​ ​ The major components of lease cost are as follows: ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2021 Operating lease cost ​ $ 4,774 ​ ​ ​ ​ Finance lease cost: ​ ​ ​ Amortization of lease assets ​ ​ 931 Interest on lease liabilities ​ ​ 16 Total lease cost ​ $ 5,721 ​ The weighted-average term and discount rate for leases are as follows: ​ ​ ​ ​ ​ As of December 31, ​ ​ 2021 ​ Weighted-average remaining lease term (years): ​ ​ Operating leases 6.6 ​ Finance leases 1.2 ​ ​ ​ ​ Weighted-average discount rate: ​ ​ Operating leases 2.3 % Finance leases 2.3 % ​ Lease liability maturities for the next five years and thereafter are as follows as of December 31, 2021: ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating Leases Finance Leases 2022 ​ $ 4,593 ​ $ 289 2023 ​ ​ 4,459 ​ ​ 59 2024 ​ ​ 4,464 ​ ​ 10 2025 ​ ​ 4,382 ​ ​ — 2026 ​ ​ 4,477 ​ ​ — Thereafter ​ ​ 8,054 ​ ​ — Total lease payments ​ ​ 30,429 ​ ​ 358 Less: Imputed interest ​ ​ (2,176) ​ ​ (6) Present value of lease liabilities ​ $ 28,253 ​ $ 352 ​ Lease liability maturities for the next five years and thereafter under the previous lease accounting standard are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2020 ​ ​ Operating Leases ​ Capital Leases 2021 ​ $ 5,442 ​ $ 915 2022 ​ 4,518 ​ 230 2023 ​ 4,459 ​ — 2024 ​ 4,464 ​ — 2025 ​ 4,382 ​ — Thereafter ​ 12,531 ​ — Total lease payments ​ $ 35,796 ​ ​ 1,145 Less amount representing interest ​ ​ ​ ​ ​ (38) Present value of minimum lease payments ​ ​ ​ ​ ​ 1,107 Less current portion ​ ​ ​ ​ ​ (882) Capital lease obligations, net of current portion ​ ​ ​ ​ $ 225 ​

GOODWILL AND OTHER INTANGIBLE A

GOODWILL AND OTHER INTANGIBLE ASSETS	12 Months Ended
	Dec. 31, 2021
GOODWILL AND OTHER INTANGIBLE ASSETS
GOODWILL AND OTHER INTANGIBLE ASSETS	8. Goodwill and other intangible assets were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ ​ 2021 ​ 2020 Goodwill ​ $ 270,041 ​ $ 16,329 Other intangible assets, net ​ ​ 2,661 ​ 2,382 Total ​ $ 272,702 ​ $ 18,711 ​ The changes in the carrying amount of goodwill are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ ​ 2021 ​ 2020 Balance, January 1 ​ $ 16,329 ​ $ — Acquisitions ​ ​ 265,867 ​ 21,089 Foreign currency translation adjustments ​ ​ (12,155) ​ ​ (4,760) Balance, December 31, gross ​ ​ 270,041 ​ ​ 16,329 Accumulated impairment losses ​ ​ — ​ ​ — Balance, December 31, net ​ $ 270,041 ​ $ 16,329 ​ The Company recognized various amortizable other intangible assets in connection with acquisitions (Note 3), including related to 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 ​ ​ ​ ​ ​ 2021 ​ 2020 Weighted average amortization period (years) ​ ​ ​ ​ ​ 4.2 ​ ​ 5.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross value ​ ​ ​ ​ $ 4,110 ​ $ 2,825 Accumulated amortization ​ ​ ​ ​ ​ (1,449) ​ ​ (443) Carrying value ​ ​ ​ ​ $ 2,661 ​ $ 2,382 ​ The following table presents amortization of intangible assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ending December 31, ​ Cost of Revenues, Software Subscriptions ​ Selling and Marketing Expense ​ Total Expense 2021 ​ $ 253 $ 813 $ 1,066 2020 ​ $ 267 $ 176 $ 443 ​ The following table presents estimated future amortization of intangible assets: ​ ​ ​ ​ ​ Year Ending December 31, ​ 2022 ​ $ 1,203 2023 ​ 743 2024 ​ 466 2025 ​ 249 Total ​ $ 2,661 ​

DEBT

DEBT	12 Months Ended
	Dec. 31, 2021
DEBT
DEBT	9. Credit Agreement On March 31, 2020, the Company entered into a credit agreement with a bank consisting of a $175,000 term loan (the “Term Loan”) and a $100,000 committed line of credit (the “Line of Credit”) (collectively, the “Credit Agreement”). Net proceeds from the Term Loan, after payment of financing fees of $2,904 and repayment of aggregate amounts outstanding under the previous credit agreement of $61,656, were used to fund a portion of the $123,185 distribution made to the stockholders on May 29, 2020 (see Note 10). A portion of the Offering proceeds was used to repay the $175,000 Term Loan in full on July 31, 2020. The Company received a refund of $468 of financing fees as a result of repayment of the Term Loan within 90 days of execution of the Credit Agreement, which was recorded as a reduction of deferred financing costs associated with the Term Loan. The Company wrote off the remaining balance of deferred financing costs associated with the Term Loan of $1,174, which was recorded as interest expense in the consolidated statement of comprehensive income (loss) for the year ended December 31, 2020. The Line of Credit matures in March 2025 The Credit Agreement is collateralized by certain assets of the Company and contains financial and operating covenants. The Company was in compliance with all financial covenants at December 31, 2021.

STOCKHOLDERS' EQUITY

STOCKHOLDERS' EQUITY	12 Months Ended
	Dec. 31, 2021
STOCKHOLDERS' EQUITY
STOCKHOLDERS' EQUITY	10. Termination of S-Corporation status In connection with termination of the Company’s S-Corporation status effective July 27, 2020, the Company had an accumulated deficit of $354,291 pertaining to the S-Corporation shareholders which was reclassified to additional paid in capital upon such termination. Recapitalization In connection with the Recapitalization, the Company: (i) effected the three-for-one Stock Split, which is reflected retrospectively in the consolidated financial statements; (ii) established the New Capital Structure; and (iii) effected the Share Exchange. In connection with the Recapitalization, repurchased shares (“Treasury Stock”) of 41,910 were retired and amounts associated with the Treasury Stock were reclassified to additional paid in capital. Prior to the Share Exchange, the Company had 147 shares of former Class A common stock and 120,443 shares of former Class B common stock outstanding. Members of a family (the “Family”) owned 99.9% of all outstanding shares of both former classes of common stock, which was comprised of 100% of the former Class A common stock and 120,270 shares of the former Class B common stock. The remaining 173 shares of former Class B common stock were owned by non-Family members. There were no dividend or liquidation preference differences between the former Class A and former Class B shares. In connection with establishing the New Capital Structure, the shareholders authorized 450,000 shares of common stock, par value $0.001 per share, and 30,000 shares of preferred stock, par value $0.001 per share. Common stock is divided into two classes, Class A with one vote per share, and Class B with ten votes per share. The rights of the holders of Class A and Class B are identical, except with respect to voting and conversion rights. Upon the transfer of Class B shares, such shares will automatically convert to an equivalent number of Class A shares with the respective voting rights attributable to such new shares. Authorized Class A and Class B shares are 300,000 and 150,000 shares, respectively. There are no dividend or liquidation preference differences between Class A and Class B. In connection with the Share Exchange, the Family members exchanged each share of former Class A and former Class B for the equivalent number of Class B shares established as part of the New Capital Structure. In addition, the non-Family members exchanged their former Class B shares for an equivalent number of Class A shares established as part of the New Capital Structure. No funds were exchanged in connection with the Share Exchange and the aggregate number of shares outstanding both immediately prior to and after the Share Exchange remained the same at 120,590. In addition, common stock equivalents, all of which were held by non-Family members and which were previously exercisable into former Class B shares, became exercisable into Class A shares established as part of the New Capital Structure Common Stock 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 also issued 12 shares and 352 shares of Class A in 2021 in connection with the vesting of RSUs and RSAs, respectively, net of 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. In April 2020, the Company issues 173 shares of former Class B common stock in connection with the exercise of options for cash of $53. These shares were exchanged for Class A common stock in connection with the Offering. On July 28, 2020, the Company sold 23,812 shares of Class A in connection with the Offering for $423,024, net of underwriting fees. Offering costs paid from these proceeds aggregated $6,222 and are reflected as a reduction of additional paid in capital in stockholders’ equity. In connection with the Offering, the Company also issued an aggregate 564 shares of Class A related to the conversion of SARs into options and the immediate exercise of these options into shares, net of 860 shares returned to the Company in lieu of payment of the exercise price and taxes due on these exercises. In addition, in 2020 the Company issued 510 shares of Class A in connection with the exercise of stock options by option holders, net of 381 shares returned to the Company in lieu of payment of the exercise price and taxes due on these exercises. The Company also issued 890 Class A shares in connection with the exercise of outstanding options and 19 Class A shares in connection with RSAs granted at the Offering, which vested immediately. The Company also issued 890 Class A shares in connection with the exercise of outstanding options and 19 Class A shares in connection with RSAs granted at the Offering, which vested immediately. The Company also issued 59 shares in connection with the ESPP Plan in 2020. A stockholder exchanged 300 shares of Class B common stock for an equivalent number of shares of Class A common stock during the year ended December 31, 2020. Distributions The Board declared distributions of $4,010 ($0.03 per share) and $123,185 ($1.02 per share) during the three months ended March 31, and June 30, 2020, respectively, and $5,706 ($0.05 per share) through July 25, 2020, pro rata to stockholders of the former Class A and Class B common stock. Tax Sharing Agreement Payments In connection with termination of the Company’s S-Corporation status effective July 27, 2020, the Company entered into a Tax Sharing Agreement with the former S-Corporation shareholders. See Note 1. The Tax Sharing Agreement, as amended, requires the Company to finalize the S-Corporation income tax returns for the short period ended July 26, 2020 and settle any remaining liability for taxes to the former S-Corporation shareholders within 15 days thereafter. All obligations of the Company under the Tax Sharing Agreement are satisfied by adjustments of additional paid in capital. Through the year ended December 31, 2021, the Company distributed $2,733 to the former S-Corporation shareholders under the Tax Sharing Agreement. 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.

EARNINGS PER SHARE

EARNINGS PER SHARE	12 Months Ended
	Dec. 31, 2021
EARNINGS PER SHARE
EARNINGS PER SHARE	11 . The tables below illustrate the calculation of basic and diluted net income (loss) per common share for the Class A common and Class B common for the periods reflected below. The weighted average shares outstanding have been retrospectively restated to reflect the Share Exchange for all periods prior to the Offering, resulting in the Class A shares representing non-Family-owned shares and Class B representing Family-owned shares for all periods presented prior to the Offering. See Note 10 for further information on the Share Exchange. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Year Ended December 31, Class A common stock: 2021 2020 2019 Numerator, basic: ​ ​ ​ ​ Net income (loss) attributable to all stockholders ​ $ (1,479) ​ $ (75,081) ​ $ 31,057 ​ Class A common stock as a percentage of total shares outstanding, basic ​ 24.12 % 8.44 % 0.08 % Net income (loss) attributable to Class A stockholders, basic ​ $ (357) ​ $ (6,335) ​ $ 23 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Numerator, diluted: ​ ​ ​ ​ Net income (loss) attributable to all stockholders ​ $ (1,479) ​ $ (75,081) ​ $ 31,057 ​ Class A common stock as a percentage of total shares outstanding, diluted ​ 24.12 % 8.44 % 3.11 % Net income (loss) attributable to Class A stockholders, diluted ​ $ (357) ​ $ (6,335) ​ $ 965 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Denominator, basic and diluted: ​ ​ ​ ​ Weighted average Class A common stock, basic ​ 35,647 ​ 11,096 ​ 118 ​ Dilutive effect of common stock equivalents (1), (2) ​ — ​ — ​ 3,743 ​ Weighted average Class A common stock, diluted ​ 35,647 ​ 11,096 ​ 3,861 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income (loss) per Class A share, basic ​ $ (0.01) ​ $ (0.57) ​ $ 0.20 ​ Net income (loss) per Class A share, diluted ​ $ (0.01) ​ $ (0.57) ​ $ 0.25 ​ 1 . ​ 2 . ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Year Ended December 31, Class B common stock: 2021 ​ 2020 2019 Numerator, basic: ​ ​ ​ ​ Net income (loss) attributable to all stockholders ​ $ (1,479) ​ $ (75,081) ​ $ 31,057 ​ Class B common stock as a percentage of total shares outstanding, basic ​ 75.88 % 91.56 % 99.92 % Net income (loss) attributable to Class B stockholders, basic ​ $ (1,122) ​ $ (68,746) ​ $ 31,034 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Numerator, diluted: ​ ​ ​ ​ Net income (loss) attributable to all stockholders ​ $ (1,479) ​ $ (75,081) ​ $ 31,057 ​ Class B common stock as a percentage of total shares outstanding, diluted ​ 75.88 % 91.56 % 96.89 % Net income (loss) attributable to Class B stockholders, diluted ​ $ (1,122) ​ $ (68,746) ​ $ 30,092 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Denominator, basic and diluted: ​ ​ ​ ​ Weighted average Class B common stock, basic ​ 112,133 ​ 120,415 ​ 120,417 ​ Dilutive effect of common stock equivalents ​ — ​ — ​ — ​ Weighted average Class B common stock, diluted ​ 112,133 ​ 120,415 ​ 120,417 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income (loss) per Class B share, basic ​ $ (0.01) ​ $ (0.57) ​ $ 0.26 ​ Net income (loss) per Class B share, diluted ​ $ (0.01) ​ $ (0.57) ​ $ 0.25 ​ ​

EMPLOYEE BENEFIT AND DEFERRED C

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS	12 Months Ended
	Dec. 31, 2021
EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS
EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS	12 . The Company maintains a 401(k) plan that covers eligible employees subject to certain age and length of service requirements. The Company matches up to 3% of eligible compensation during the period in which an eligible participant contributes to the plan. Matching contributions were $4,062, $4,011 and $3,419 for the years ended December 31, 2021, 2020 and 2019, respectively. In addition, a discretionary profit-sharing contribution of 3% of eligible compensation for eligible employees was approved and aggregated $3,994, $4,035 and $3,363 for the years ended December 31, 2021, 2020 and 2019, respectively, and is reflected in accrued salaries and benefits in the consolidated balance sheets. 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 will be 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 (“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 (“accrued LTR Award Opportunities”). At December 31, 2021, the Company has two open Reward Performance Periods that would be eligible for payment in 2022 and 2023. Compensation expense associated with LTR plan was $3,059, 3,027, and $2,462 for the years ended December 31, 2021, 2020 and 2019, respectively. Amounts paid in 2021 and 2020 for the LTR plan was $1,981 and $2,796, respectively. Amounts estimated to be paid in 2022 and 2023 for the LTR plan are $4,060 and $1,778, respectively, which amounts are reflected in deferred compensation, current and deferred compensation, net of current portion, respectively, in the consolidated balance sheet as of December 31, 2021. Stock-Based Award Plans On the effective date of the Offering, the Company adopted the 2020 Plan and the ESPP. 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, SARs 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 common at the ESPP discount through payroll deductions, or through lump sum payments during the initial offering period only (July 28 to November 30, 2020). 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, 2022 and 2021 aggregated $281 and $246 as of December 31, 2021 and 2020, respectively. Prior to the adoption of the 2020 Plan, the Company had a SAR plan for the purpose of providing incentives to key members of management and consultants to contribute to the growth and financial success of the Company. As a result of the Offering, SAR participants were offered the option to either redeem their SARs upon the occurrence of the Offering or amend their SARs pursuant to which, upon effectiveness of the 2020 Plan, such SARs would become options to purchase shares of Class A common stock under the 2020 Plan (the “SAR Exchange Offer”). All SAR participants eligible to receive the SAR Exchange Offer accepted and had their outstanding SARs, which aggregated 12,038, converted to options with equivalent terms under the 2020 Plan at the Offering effective date (the “Converted SARs”). This was considered a modification of these SAR awards. The SAR plan was retired (“Retired SAR Plan”) and any future SARs will be granted under the 2020 Plan. Prior to the adoption of the 2020 Plan, the Company had options outstanding to purchase 3,676 shares of former Class B common stock. U pon the effectiveness of the Offering, these options were amended and exchanged for options to purchase an equivalent number of Class A shares at the same exercise price and vesting, subject to the terms of the 2020 Plan except with regard to certain terms of the original option agreements primarily with respect to expiration in connection with a Triggering Event (the “Amended Options”). 2020 Plan Upon commencement of the 2020 Plan, an aggregate of 16,500 shares of our Class A common stock were available for issuance. The number of shares available for issuance will be 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 common stock 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 common 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, 2021, 6,490 shares of our Class A common 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, 2021. 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. Retired SAR Plan The Retired SAR Plan enabled the Company to grant awards (“SAR Awards”) as a fixed number of shares of former Class B common stock (“SAR Units”). SAR Units outstanding aggregated 12,276 at December 31, 2019. SAR Units were issued at the equivalent of the fair value of the equivalent number of shares of the Company’s former Class B common stock on the grant date (“Base Value”), as determined by the Board with assistance from management and an independent third-party valuation provider, and compensation recorded based upon the appreciation of the SAR Units in excess of the Base Value over the requisite service period. SAR Awards were exercisable upon 50% vesting or upon the occurrence of a triggering event. SAR Awards were settled in cash only, not through the issuance of shares. The SAR Exchange Offer resulted in eligible SAR participants amending their SAR Units pursuant to which, upon effectiveness of the Company’s 2020 Plan, such SAR Units were exchanged for options under the 2020 Plan. Effective July 13, 2020, the SAR Exchange Offer period ended and all SAR participants eligible to receive the offer accepted and had their outstanding SAR Units converted to options with equivalent terms under the 2020 Plan on the effective date of the plan upon the Offering. This was considered an accounting modification of these SAR Awards. Converted SARs with either no expiration date or that expired during calendar year 2020 were converted to options and automatically exercised into shares (the “Auto Exercise New Options”) on the effective date of the Offering. Shares issued in connection with the Auto Exercise New Options were net of the number of shares of common stock necessary to satisfy the aggregate exercise price and the tax withholding obligation of such options of $13,835. The Auto Exercise New Option participants also had the ability to require the Company to repurchase all or a portion of these on the Offering effective date for cash based on the Offering price of $19.00 per share, which aggregated $9,054. The aggregate of these amounts of $22,889 is reflected as a reduction of cash provided by operating activities as these payment requirements arose when the original SARs were liability-classified prior to their conversion and exercise. Management continued to record changes in the intrinsic value of the SAR Units in 2020 up to the date on which management determined the Company was considered to have become a public entity. Management measured the change in accounting policy of $2,422 in accordance with ASC 718 during the year ended December 31, 2021, which included $1,299 of vested Converted SARs that were recognized as compensation expense during this period, with the remaining $1,122 of unvested Converted SARs being recognized as compensation expense over the remaining service period of one one The assumptions used in the Black-Scholes model to determine the fair value of the Converted SARs on the modification date are as follows: ​ ​ ​ ​ ​ ​ Fair market value of common stock ​ $ 19.00 ​ Volatility 36.7 % Expected term (years) 6.5 ​ Expected dividend yield — % Risk-free interest rate 0.4 % ​ As of the modification date, 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 of the Converted SARs, which ranges from within one year to ten years. The Company does not expect to pay dividends after the Offering. 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 SAR grants. Prior to the Offering, the fair value of the common stock underlying the SAR Awards was determined by the Board with assistance from management and an independent third-party valuation firm. The determination of value used the market and income approaches, with an adjustment for marketability discount pertinent to private company entities in arriving at the per share fair value (the “valuation methodology”). Under the market approach, the guideline public company method is used, which estimates the fair value of the Company based on market prices of stock of guideline public companies. The income approach involves projecting the future benefits of owning an asset and estimating the present value of those future benefits by discounting them based upon the time value of money and the investment risks associated with ownership. At the end of 2019, due to the consideration by the Board of pursuing the Offering, the valuation methodology began to consider the impact of such an event on the value of the Company’s common stock underlying the awards. As the Company approached the Offering effective date, this resulted in increases in the value of the SAR Awards which resulted in corresponding increases to compensation expense for the year ended December 31, 2020 which exceeded historical results. The below table represents SAR activity for the following periods: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Units Range of ​ Vested Nonvested Total Grant Values Outstanding at January 1, 2019 5,889 4,782 10,671 ​ $ 0.92–$3.17 Granted 297 2,112 2,409 ​ $ 3.73 Exercised (609) — (609) ​ $ 1.31–$2.50 Forfeited — (195) (195) ​ $ 2.13–$2.50 Vested 630 (630) — ​ Outstanding at December 31, 2019 6,207 6,069 12,276 ​ $ 0.92–$3.73 Granted 21 681 702 ​ $ 4.70 Exercised (877) — (877) ​ $ 1.31–$2.50 Forfeited — (63) (63) ​ $ 2.50 Vested 1,410 (1,410) — ​ Converted (6,761) (5,277) (12,038) ​ $ 0.92–$4.70 Outstanding at December 31, 2020 — — — ​ ​ ​ ​ Prior to the Offering, the weighted average grant date intrinsic value of the SARs on grant date was zero as the Company’s Board granted all awards at a price per share not less than the per share fair value of the Company’s former Class B common stock underlying such awards on the date of grant. At the Offering effective date, the liability for total recognized compensation for vested SAR Awards of $143,519 was reclassified to additional paid in capital as these awards were reclassified to equity-based awards on this date subject to the terms of the 2020 Plan. Unrecognized compensation for unvested SAR awards of $44,342 will be recognized as compensation expense under the 2020 Plan over the respective service periods of one Amended Options On July 20, 2020, the Amended Options resulted from the Board amending the outstanding options to provide for their exchange for options to purchase an equivalent number of Class A shares available under the 2020 Plan at the same exercise price, vesting and term The amendment of the options was deemed an accounting modification. No incremental compensation was recorded in connection with this modification as it was determined that the value of the Amended Options was the same both before and after the modification. In the event of the sale of at least 50% of the Company’s stock or all the assets of the Company (“Triggering Event”) in a single or multiple transactions, the option holders have the right to exercise their options and sell their related shares in connection with the transactions. Unexercised options expire after a Triggering Event. In the event of a sale of at least 25% of the Company’s assets to an unrelated third-party in a single or multiple transactions (“Partial Triggering Event”), the option holders have the right to exercise a portion of their options pro rata based on the sales price and sell their related shares in connection with the transaction. Unexercised options remaining after a Partial Triggering Event remain outstanding. In addition, in the event stockholders owning at least 51% of the outstanding stock of the Company (the “selling stockholders”) sell a portion of their stock to an unrelated third-party, the option holders have the right to exercise and sell an amount of options in the same proportion as the selling stockholders (a “tag-along right”). The option holders may also be required to exercise all their outstanding options and sell all related shares in the event the selling stockholders sell at least 51% of their ownership to an unrelated third-party (a “drag-along right”). Prior to the amendment, the options permitted holders to put their exercised shares back to the Company, thus the options were classified as temporary equity and included in “Options for Redeemable Shares” on the consolidated balance sheets. The Company recorded increases in the value of Options for Redeemable Shares of $51,833 and $2,763 during the years ended December 31, 2020 and 2019, respectively. The option holders’ ability to put the exercised Amended Option shares to the Company in order to attain liquidity was exchanged for the right by the holders to exercise these options and sell the related shares on the NASDAQ exchange. As a result of this put right no longer being applicable, the options were no longer considered temporary equity and were reclassified to stockholders’ equity in the amount of $69,177 during the year ended December 31, 2020. The following table summarizes activity for the Amended Options for the periods presented: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ Average ​ ​ ​ ​ ​ ​ ​ Average ​ Remaining ​ Aggregate ​ ​ ​ ​ ​ Exercise ​ Contractual ​ Intrinsic Amended Option Activity ​ Units ​ ​ Price ​ Life (Years) ​ Value Outstanding at January 1, 2019 ​ 4,125 ​ $ 0.20 ​ * ​ $ 14,581 Exercised ​ (276) ​ $ 0.25 ​ ​ ​ $ 957 Outstanding at December 31, 2019 ​ 3,849 ​ $ 0.19 ​ * ​ $ 17,344 Exercised through June 30 ​ (173) ​ $ 0.30 ​ ​ ​ $ 759 Amendment and exchange of options ​ (3,676) ​ $ 0.19 ​ * ​ $ 69,177 Outstanding at December 31, 2020 ​ — ​ ​ ​ ​ ​ ​ ​ ​ *Options have indefinite contractual lives ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Options under 2020 Plan The following table summarizes activity for options outstanding under the 2020 Plan for the periods presented: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ Average ​ ​ ​ ​ ​ ​ ​ Average ​ Remaining ​ Aggregate ​ ​ ​ ​ ​ Exercise ​ Contractual ​ Intrinsic 2020 Plan Option Activity ​ Units ​ ​ Price ​ Life (Years) ​ Value Outstanding at January 1, 2020 ​ — ​ ​ — ​ ​ ​ ​ ​ Issued in connection with Converted SARs ​ 12,038 ​ $ 2.76 ​ ​ ​ ​ ​ Issued in connection with Amended Options ​ 3,676 ​ $ 0.19 ​ * ​ ​ ​ Total options granted ​ 15,714 ​ $ 2.16 ​ ​ ​ ​ ​ Forfeited ​ (156) ​ $ 3.29 ​ ​ ​ ​ ​ Exercised ​ (3,682) ​ $ 1.21 ​ ​ ​ ​ ​ 2020 Plan options outstanding at December 31, 2020 ​ 11,876 ​ $ 2.44 ​ 5.3 ​ $ 384,883 Granted ​ 779 ​ $ 23.06 ​ ​ ​ ​ ​ Forfeited ​ (292) ​ $ 4.06 ​ ​ ​ ​ ​ Exercised ​ (2,863) ​ $ 2.04 ​ ​ ​ ​ ​ 2020 Plan options outstanding at December 31, 2021 ​ 9,500 ​ $ 4.20 ​ 5.2 ​ $ 110,843 2020 Plan options exercisable at December 31, 2021 6,169 ​ $ 2.39 3.9 ​ $ 83,188 *Amended Options have indefinite contractual lives ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The detail of options outstanding, vested and exercisable under the 2020 Plan as of December 31, 2021 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 1,854 — 1,854 — $2.15 462 3.1 462 3.1 $2.50 2,186 4.5 2,186 4.5 $2.67 419 5.2 42 5.1 $3.17 1,196 6.3 446 6.3 $3.73 ​ 1,932 ​ 7.8 ​ 1,061 ​ 7.8 $4.70 ​ 683 ​ 8.1 ​ — ​ — $18.47 ​ 213 ​ 9.9 ​ — ​ — $18.96 ​ 235 ​ 9.6 ​ 105 ​ 9.6 $19.00 69 9.7 — — $32.16 251 9.2 13 9.2 ​ 9,500 ​ ​ 6,169 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 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 common stock underlying the options on the date of grant. Compensation expense for new option awards issued subsequent to the Offering to participants under the 2020 Plan are measured based on the grant date fair value of the awards and recognized in the consolidated statements of comprehensive income (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 during various quarters in 2021. 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 ​ ​ Q1 2021 ​ Q2 2021 ​ Q3 2021 Q3 2021 ​ ​ Q4 2021 ​ Fair market value of common stock ​ $ 32.16 ​ ​ $ 17.66 ​ ​ $ 18.96 ​ $ 19.00 ​ ​ $ 18.47 ​ Volatility 36.8 % ​ 36.8 % ​ 37.1 % ​ 37.1 % ​ 37.4 % Expected term (years) 6.0 ​ ​ 6.0 ​ ​ 5.0 ​ ​ 5.0 ​ ​ 5.0 ​ Expected dividend yield — % ​ — % ​ — % ​ — % ​ — % Risk-free interest rate 0.4 % ​ 0.4 % ​ 0.8 % ​ 0.9 % ​ 1.3 % ​ The fair market value of common stock reflects the market closing price on NASDAQ 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, 2021, $18,742 of unrecognized compensation expense associated with the options and Converted SARs is expected to be recognized over a weighted average period of approximately 2.8 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, 2020 — ​ ​ ​ Granted 101 ​ $ 23.80 Total at December 31, 2020 ​ 101 ​ ​ 23.80 Granted ​ 478 ​ ​ 27.07 Vested (15) ​ ​ 29.67 Forfeited (34) ​ ​ 25.18 Outstanding at December 31, 2021 ​ 530 ​ $ 26.49 ​ 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 income (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. At December 31, 2021, there are 1,007 shares of our Class A common stock (“PSUs”) with an aggregate grant date fair value of $17,779 that will be accounted for as post-acquisition compensation expense over the vesting period if targets are achieved. The performance-based condition will be satisfied upon meeting certain performance targets for the year ended 2023. As of December 31, 2021, it is not probable that these targets will be met, thus no compensation expense has been recorded to date related to these PSUs. 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, 2020 — ​ ​ ​ Granted 694 ​ $ 19.00 Vested (21) ​ 19.00 Forfeited (3) ​ 19.00 Outstanding at December 31, 2020 ​ 670 ​ ​ 19.00 Granted ​ 59 ​ ​ 17.66 Vested ​ (363) ​ ​ 19.00 Forfeited ​ (40) ​ ​ 19.00 Outstanding at December 31, 2021 326 ​ $ 18.76 ​ 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 income (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 common stock 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. On the first trading day of each offering period, each participant will automatically be granted an option to purchase shares of Class A common. 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 common 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 common. 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, 2021 and 2020 there was approximately $233 and $218, 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 2022 and 2021, respectively. The fair value of ESPP purchase rights is comprised of the value of the 15% ESPP discount and the value associated with the Call/Put over the ESPP offering period. The value of the Call/Put for the respective offering periods was estimated using the Black-Scholes model with the following assumptions: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Offering Period Ending ​ ​ 11/30/2020 ​ 5/31/2021 ​ 11/30/2021 ​ 5/31/2022 Fair market value of common stock $ 19.00 ​ ​ $ 25.83 ​ ​ $ 18.89 ​ ​ $ 17.38 ​ Volatility ​ 35.0 % ​ 35.1 % ​ 35.1 % ​ 37.3 % Expected term (years) ​ 0.3 ​ ​ 0.5 ​ ​ 0.5 ​ ​ 0.5 ​ Expected dividend yield ​ - % ​ - % ​ - % ​ - % Risk-free interest rate ​ 0.1 % ​ 0.1 % ​ 0.1 % ​ 0.1 % ​ The Company lacks 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 of the ESPP offering period, which is generally six months except for the initial offering period which was from July 28 to November 30, 2020. The Company does not expect to pay dividends after the Offering. 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 stock-based awards and the ESPP as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Year Ended December 31, ​ 2021 2020 2019 Stock-based compensation expense: ​ ​ ​ SARs and Converted SARs ​ $ 16,023 ​ $ 143,123 ​ $ 9,460 Stock options ​ 1,510 ​ — ​ — RSUs ​ 2,964 ​ 171 ​ — RSAs ​ ​ 5,126 ​ ​ 4,284 ​ ​ — ESPP ​ 537 ​ 326 ​ — Total stock-based compensation expense ​ $ 26,160 ​ $ 147,904 ​ $ 9,460 ​ The Company recognized stock-based compensation cost in the consolidated statements of comprehensive income (loss) as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Year Ended December 31, ​ 2021 2020 2019 Stock-based compensation expense: ​ ​ ​ ​ ​ ​ ​ ​ ​ Cost of revenues, software subscriptions ​ $ 2,336 ​ $ 14,663 $ 946 Cost of revenues, services ​ 2,648 ​ 21,472 1,419 Research and development ​ 2,620 ​ 14,694 946 Selling and marketing ​ 6,371 ​ 29,551 1,892 General and administrative ​ 12,185 ​ 67,524 4,257 Total stock-based compensation expense ​ $ 26,160 ​ $ 147,904 ​ $ 9,460 ​

RELATED PARTIES

RELATED PARTIES	12 Months Ended
	Dec. 31, 2021
RELATED PARTIES
RELATED PARTIES	13. During 2019, certain stockholders of the Company repaid non-interest bearing amounts due to the Company of a short-term nature and no amounts were outstanding at December 31, 2020.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2021
COMMITMENTS AND CONTINGENCIES
COMMITMENTS AND CONTINGENCIES	14. 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. ​

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2021
INCOME TAXES
INCOME TAXES	15. Prior to revocation of the S-Election on July 27, 2020, the Company had historically been taxed as an S-Corporation for U.S. federal income tax purposes and income tax purposes in most states. As a result, income was not subject to U.S. federal income taxes or state income taxes in those states where the S-Corporation status was recognized. Therefore, previous to July 27, 2020, no provision or liability for federal or state income tax had been provided in the consolidated financial statements except for those states where the S-Corporation status was not recognized, or where states imposed a tax on S-Corporations. The provision for income tax in the historical periods prior to the Offering consisted of these state taxes and taxes from certain foreign jurisdictions where the Company was subject to tax. Upon revocation of the S-Election, the Company converted to a C-Corporation resulting in tax at the corporate level on net income or losses for subsequent periods. The revocation of the S-Corporation status was treated as a change in tax status resulting in the recording of the deferred tax effects of such change to income from continuing operations on the date the S-Corporation status revoked. The termination of the S-Corporation election had a material impact on the Company’s 2020 results of operations and financial condition. As such, the Company’s income tax provision for periods subsequent to the C-Corporation conversion will not be comparable to periods prior to such conversion. For U.S. corporate income tax purposes, the Company apportioned its 2020 results between the S-Corporation and C-Corporation periods. This allocation effectively resulted in a blended income tax rate for the 2020 year, as only the C-Corporation net losses were subject to both U.S. federal and state corporate income tax, while the S-Corporation earnings were only subject to tax in those states that tax S-Corporations or do not recognize S-Corporation status. Deferred income taxes for the year ended December 31, 2020, includes an adjustment for the three months ended September 30, 2020 of $3,856 recorded in connection with the understatement of certain stock award exercise activity in connection with the Company’s Offering, which occurred in such quarter. Refer to Note 1, Revision of Previously Issued Financial Statements. The components of net income (loss) before income taxes, by geography, are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Year Ended December 31, ​ ​ 2021 2020 2019 U.S. ​ $ 5,608 ​ $ (107,959) ​ $ 32,131 Foreign ​ (9,534) ​ 90 ​ (1,229) Net income (loss) before income taxes ​ $ (3,926) ​ $ (107,869) ​ $ 30,902 ​ Income tax expense (benefit) consists of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Year Ended December 31, ​ ​ 2021 2020 2019 Current income taxes: ​ ​ ​ Federal ​ $ — ​ $ — ​ $ — State and local ​ ​ 155 ​ ​ 617 ​ ​ 578 Foreign ​ 468 ​ 94 ​ 115 Total current ​ 623 ​ 711 ​ 693 Deferred income taxes: ​ ​ ​ Federal ​ ​ (1,849) ​ ​ (27,076) ​ ​ — State and local ​ (7) ​ (6,491) ​ (677) Foreign ​ (1,214) ​ 68 ​ (171) Total deferred ​ (3,070) ​ (33,499) ​ (848) Income tax benefit ​ $ (2,447) ​ $ (32,788) ​ $ (155) ​ During the year ended December 31, 2021, the Company recognized a $89 income tax expense in accumulated other comprehensive loss relating to recognized gains from foreign currency translation adjustments and revaluations. During the year ended December 31, 2020, the Company recognized a $55 income tax benefit in accumulated other comprehensive loss relating to recognized losses from foreign currency translation adjustments and revaluations. ​ The reconciliation of the effective tax rate to tax at the statutory rates for the years ended December 31 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 2020 2019 ​ ​ Total ​ Tax Rate ​ Total ​ Tax Rate Total ​ Tax Rate Pretax net (loss) income ​ $ (3,926) ​ $ (107,869) ​ $ 30,902 ​ Taxes: ​ ​ ​ ​ U.S. federal income tax at statutory rate ​ $ (825) 21.0 % $ (22,652) 21.0 % $ 6,489 21.0 % State income taxes ​ ​ 678 (17.3) % ​ (1,811) 1.7 % ​ (98) (0.3) % Tax effect of S-Corporation status ​ ​ — ​ — % ​ 21,325 ​ (19.8) % ​ (6,489) ​ (21.0) % Impact of change in tax status ​ ​ — ​ — % ​ (25,396) ​ 23.5 % ​ — ​ — % Stock-based compensation expense ​ ​ (4,550) ​ 115.9 % ​ (5,809) ​ 5.4 % ​ — ​ — % Impact of foreign operations ​ 954 ​ (24.3) % (56) ​ 0.1 % (57) (0.2) % Return to provision adjustments ​ ​ (464) ​ 11.8 % ​ — ​ — % ​ — ​ — % Transaction costs ​ ​ 1,082 ​ (27.6) % ​ — ​ — % ​ — ​ — % US taxation of foreign earnings ​ ​ 144 ​ (3.7) % ​ 81 ​ (0.1) % ​ — ​ — % Nondeductible compensation ​ ​ 682 ​ (17.4) % ​ 883 ​ (0.8) % ​ — ​ — % Tax credits ​ ​ (488) ​ 12.4 % ​ (44) ​ 0.0 % ​ — ​ — % Change in valuation allowance ​ ​ 373 ​ (9.5) % ​ 109 ​ (0.1) % ​ — ​ — % Profit sharing deduction ​ ​ (46) ​ 1.2 % ​ — ​ — % ​ — ​ — % Other permanent items, net ​ ​ 13 (0.2) % ​ 582 (0.5) % ​ — ​ — % Taxes and effective tax rate ​ $ (2,447) 62.3 % $ (32,788) 30.4 % $ (155) (0.5) % ​ The The effective ​ Significant components of the Company’s net deferred tax assets (liabilities) are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, Deferred tax assets: 2021 2020 Deferred revenue ​ $ 3,788 ​ $ 3,189 State operating loss carry forwards ​ 3,894 ​ 2,595 Federal and foreign loss carry forwards ​ 21,617 ​ 13,388 Accrued expenses ​ 2,023 ​ 2,324 Accrued variable compensation ​ 3,110 ​ 3,414 Deferred and stock-based compensation ​ 24,971 ​ 29,188 Operating lease liabilities ​ ​ 7,204 ​ ​ 2,429 Tax credits ​ ​ 532 ​ ​ 44 Other ​ 53 ​ 303 Deferred tax assets ​ 67,192 ​ 56,874 Valuation allowance ​ (1,839) ​ (1,507) Total deferred tax assets ​ 65,353 ​ 55,367 Deferred tax liabilities: ​ ​ Depreciation and amortization ​ (26,269) ​ (19,998) Prepaid expenses ​ ​ (1,329) ​ ​ (1,557) Right of use asset ​ (5,120) ​ — Total deferred tax liabilities ​ (32,718) ​ (21,555) Net deferred tax asset ​ $ 32,635 ​ $ 33,812 ​ ​ ​ ​ ​ ​ ​ Classification in the consolidated balance sheets: ​ ​ ​ ​ ​ ​ Deferred income tax asset ​ $ 35,298 ​ $ 33,830 Deferred other liabilities ​ ​ (2,663) ​ ​ (18) Net deferred tax asset ​ $ 32,635 ​ $ 33,812 ​ At December 31, 2021, the Company has available U.S. federal operating loss carry forwards of $89,594, and U.S. state operating loss carry forwards of $71,013. The federal operating loss will carryforward indefinitely and the state operating loss will expire at varying dates beginning in 2028. The Company also has $532 of federal tax credits available that begin to expire in 2040. Management expects to fully use these U.S. federal and U.S. state operating loss and credit carry forwards. At December 31, 2021, the Company has available foreign operating losses of approximately $15,318, which carry forward indefinitely. In addition, the Company has $55 of foreign non-operating losses, which carry forward indefinitely. A valuation allowance for a portion of the foreign operating and all of the foreign non-operating losses are recorded at December 31, 2021 and 2020. At December 31, 2021 and 2020, the Company has a valuation allowance of ($1,839) and ($1,507), respectively, primarily against certain net deferred tax assets, including losses, in foreign jurisdictions. The net increase in the total valuation allowance of ($322) during December 31, 2021 primarily related to the recording of a valuation allowance on net deferred tax assets in a foreign jurisdiction that, in the judgment of management, are not more likely than not to be realized, as well as changes in foreign exchange rates. The net increase in the valuation allowance of ($1,461) during December 31, 2020, primarily related to recognizing valuation allowances through purchase accounting related to net operating losses associated with Systax. 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, 2018 through December 31, 2021 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, 2016 through December 31, 2021 remain subject to examination by the respective authorities.

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	12 Months Ended
	Dec. 31, 2021
SUBSEQUENT EVENTS
SUBSEQUENT EVENTS	16. On March 8, 2022, the Company entered into the Second Amendment to Credit Agreement (the “Second Amendment”), with a banking syndicate, which amended the Credit Agreement providing for, among other modifications, (a) a new term loan in the aggregate amount of $50,000 (the “New Term Loan”), (b) an extension of the maturity date of the revolving facility from March 2025 to March 2027, (c) an upsize in the revolving credit commitment to an aggregate amount of $200,000 (the “Amended Line of Credit”), (d) 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 term SOFR plus an applicable margin (the “Term SOFR Option”), (e) modifications to the financial covenant performance levels which determine applicable margins and (f) modifications to certain covenants and events of default. As of the date we entered into the Second Amendment, the applicable margin with respect to the New Base Rate Option and Term SOFR Option applicable to the Amended Line of Credit and New Term Loan borrowings were 0.00% and 1.00%, respectively. Net proceeds from the New Term Loan shall be used to fund ongoing working capital, capital expenditures, permitted distributions, permitted acquisitions and general corporate purposes of the Company and its subsidiaries. The New Line of Credit had no outstanding borrowings at March 16, 2022.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2021
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Nature of Business	Nature of Business Vertex, Inc. (“Vertex”) and its consolidated subsidiaries (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 has a 65% controlling equity interest in Systax Sistemas Fiscais LTDA (“Systax”), a provider of Brazilian transaction tax content and software. Systax was determined to be a Variable Interest Entity (“VIE”) and its accounts have been included in the consolidated financial statements from the acquisition date. 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, consolidated statements of comprehensive income (loss), consolidated statements of cash flows, and consolidated statements of changes in stockholders’ equity (deficit) have been revised to correct for certain immaterial errors, as discussed below. During the fourth quarter of 2021, management identified certain immaterial errors impacting previously issued financial statements beginning as of and for the three and nine month periods ended September 30, 2020 and subsequent annual and quarterly reporting periods through September 30, 2021. Specifically, management identified an understatement of the deferred tax benefit and deferred tax assets Management assessed the materiality of this presentation on prior period consolidated financial statements in accordance with the SEC Staff Accounting Bulletin No. 99, “Materiality”, codified in Accounting Standards Codification (“ASC”) Topic 250, Accounting Changes and Error Corrections . Based on this assessment, management concluded that the error correction is not material to any previously presented interim or annual financial statements. In accordance has revised the previously reported financial information in this Annual Report on Form 10-K The consolidated balance sheets have been revised to reflect the correction as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As Reported ​ Revision ​ As Revised September 30, 2020 (unaudited) ​ ​ ​ ​ ​ ​ ​ Deferred income tax asset $ 32,440 ​ $ 3,856 $ 36,296 Total assets ​ ​ 514,934 ​ ​ 3,856 ​ 518,790 Retained earnings ​ ​ 21,696 ​ ​ 3,856 ​ ​ 25,552 Total stockholders' equity ​ ​ 218,561 ​ ​ 3,856 ​ 222,417 Total liabilities and stockholders' equity ​ ​ 514,934 ​ ​ 3,856 ​ 518,790 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ Deferred income tax asset $ 29,974 ​ $ 3,856 $ 33,830 Total assets ​ ​ 554,928 ​ ​ 3,856 ​ 558,784 Retained earnings ​ ​ 21,926 ​ ​ 3,856 ​ ​ 25,782 Total stockholders' equity ​ ​ 225,486 ​ ​ 3,856 ​ 229,342 Total liabilities and stockholders' equity ​ ​ 554,928 ​ ​ 3,856 ​ 558,784 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2021 (unaudited) ​ ​ ​ ​ ​ ​ ​ Deferred income tax asset $ 30,373 ​ $ 3,856 $ 34,229 Total assets ​ ​ 558,337 ​ ​ 3,856 ​ ​ 562,193 Retained earnings ​ ​ 24,722 ​ ​ 3,856 ​ ​ 28,578 Total stockholders' equity ​ ​ 226,576 ​ ​ 3,856 ​ ​ 230,432 Total liabilities and stockholders' equity ​ ​ 558,337 ​ ​ 3,856 ​ ​ 562,193 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, 2021 (unaudited) ​ ​ ​ ​ ​ ​ ​ Deferred income tax asset $ 32,573 ​ $ 3,856 $ 36,429 Total assets ​ ​ 609,529 ​ ​ 3,856 ​ ​ 613,385 Retained earnings ​ ​ 25,530 ​ ​ 3,856 ​ ​ 29,386 Total stockholders' equity ​ ​ 227,844 ​ ​ 3,856 ​ ​ 231,700 Total liabilities and stockholders' equity ​ ​ 609,529 ​ ​ 3,856 ​ ​ 613,385 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2021 (unaudited) ​ ​ ​ ​ ​ ​ ​ Deferred income tax asset $ 32,816 ​ $ 3,856 $ 36,672 Total assets ​ ​ 645,844 ​ ​ 3,856 ​ ​ 649,700 Retained earnings ​ ​ 21,582 ​ ​ 3,856 ​ ​ 25,438 Total stockholders' equity ​ ​ 224,211 ​ ​ 3,856 ​ ​ 228,067 Total liabilities and stockholders' equity ​ ​ 645,844 ​ ​ 3,856 ​ ​ 649,700 ​ The consolidated statements of comprehensive income (loss) have been revised to reflect the correction as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended September 30, 2020 ​ Nine months ended September 30, 2020 (unaudited) As Reported ​ Revision ​ As Revised ​ As Reported ​ Revision ​ As Revised Income tax benefit $ (30,773) ​ $ (3,856) $ (34,629) ​ $ (31,508) ​ $ (3,856) $ (35,364) Net loss ​ ​ (21,028) ​ ​ 3,856 ​ ​ (17,172) ​ ​ (79,167) ​ ​ 3,856 ​ ​ (75,311) Total comprehensive loss ​ ​ (21,266) ​ ​ 3,856 ​ ​ (17,410) ​ ​ (82,679) ​ ​ 3,856 ​ ​ (78,823) Net loss attributable to Class A stockholders, basic ​ ​ (2,751) ​ ​ 505 ​ ​ (2,246) ​ ​ (2,427) ​ ​ 149 ​ ​ (2,278) Net loss per Class A share, basic ​ ​ (0.15) ​ ​ 0.03 ​ ​ (0.12) ​ ​ (0.40) ​ ​ 0.03 ​ ​ (0.37) Net loss attributable to Class A stockholders, diluted ​ ​ (2,751) ​ ​ 505 ​ ​ (2,246) ​ ​ (2,427) ​ ​ 149 ​ ​ (2,278) Net loss per Class A share, diluted ​ ​ (0.15) ​ ​ 0.03 ​ ​ (0.12) ​ ​ (0.40) ​ ​ 0.03 ​ ​ (0.37) Net loss attributable to Class B stockholders, basic ​ ​ (18,277) ​ ​ 3,351 ​ ​ (14,926) ​ ​ (76,740) ​ ​ 3,707 ​ ​ (73,033) Net loss per Class B share, basic ​ ​ (0.15) ​ ​ 0.03 ​ ​ (0.12) ​ ​ (0.64) ​ ​ 0.03 ​ ​ (0.61) Net loss attributable to Class B stockholders, diluted ​ ​ (18,277) ​ ​ 3,351 ​ ​ (14,926) ​ ​ (76,740) ​ ​ 3,707 ​ ​ (73,033) Net loss per Class B share, diluted ​ ​ (0.15) ​ ​ 0.03 ​ ​ (0.12) ​ ​ (0.64) ​ ​ 0.03 ​ ​ (0.61) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As Reported ​ Revision ​ As Revised Income tax benefit ​ ​ ​ ​ ​ ​ ​ ​ ​ $ (28,932) ​ $ (3,856) $ (32,788) Net loss ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (78,937) ​ ​ 3,856 ​ ​ (75,081) Total comprehensive loss ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (81,573) ​ ​ 3,856 ​ ​ (77,717) Net loss attributable to Class A stockholders, basic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (6,660) ​ ​ 325 ​ ​ (6,335) Net loss per Class A share, basic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (0.60) ​ ​ 0.03 ​ ​ (0.57) Net loss attributable to Class A stockholders, diluted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (6,660) ​ ​ 325 ​ ​ (6,335) Net loss per Class A share, diluted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (0.60) ​ ​ 0.03 ​ ​ (0.57) Net loss attributable to Class B stockholders, basic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (72,277) ​ ​ 3,531 ​ ​ (68,746) Net loss per Class B share, basic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (0.60) ​ ​ 0.03 ​ ​ (0.57) Net loss attributable to Class B stockholders, diluted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (72,277) ​ ​ 3,531 ​ ​ (68,746) Net loss per Class B share, diluted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (0.60) ​ ​ 0.03 ​ ​ (0.57) ​ The consolidated statements of cash flows have been revised to reflect the correction as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine months ended September 30, 2020 (unaudited) As Reported ​ Revision ​ As Revised Net loss $ (79,167) ​ $ 3,856 $ (75,311) Deferred income tax benefit ​ ​ (32,004) ​ ​ (3,856) ​ ​ (35,860) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended December 31, 2020 ​ ​ As Reported ​ Revision ​ As Revised Net loss $ (78,937) ​ $ 3,856 $ (75,081) Deferred income tax benefit ​ ​ (29,643) ​ ​ (3,856) ​ ​ (33,499) ​ The consolidated statements of changes in stockholders’ equity (deficit) have been revised to reflect the correction as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended September 30, 2020 (unaudited) ​ As Reported ​ Revision ​ As Revised Net loss ​ $ (21,028) ​ $ 3,856 ​ $ (17,172) Retained earnings ​ ​ 21,696 ​ ​ 3,856 ​ ​ 25,552 Total stockholders' equity ​ ​ 218,561 ​ ​ 3,856 ​ ​ 222,417 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended December 31, 2020 ​ ​ As Reported ​ Revision ​ As Revised Net loss ​ $ (78,937) ​ $ 3,856 ​ $ (75,081) Retained earnings ​ ​ 21,926 ​ ​ 3,856 ​ ​ 25,782 Total stockholders' equity ​ ​ 225,486 ​ ​ 3,856 ​ ​ 229,342 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended March 31, 2021 (unaudited) ​ As Reported ​ Revision ​ As Revised Retained earnings ​ $ 24,722 ​ $ 3,856 ​ $ 28,578 Total stockholders' equity ​ ​ 226,576 ​ ​ 3,856 ​ ​ 230,432 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three and six months ended June 30, 2021 (unaudited) As Reported ​ Revision ​ As Revised Retained earnings ​ $ 25,530 ​ $ 3,856 ​ $ 29,386 Total stockholders' equity ​ ​ 227,844 ​ ​ 3,856 ​ ​ 231,700 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three and nine months ended September 30, 2021 (unaudited) As Reported ​ Revision ​ As Revised Retained earnings ​ $ 21,582 ​ $ 3,856 ​ $ 25,438 Total stockholders' equity ​ ​ 224,211 ​ ​ 3,856 ​ ​ 228,067
Registration of Company Stock and Initial Public Offering	Registration of Company Stock and Initial Public Offering On July 28, 2020, the Company filed its amended and restated certificate of incorporation with the Delaware Secretary of State to: (i) effect a three-for-one forward stock split (the “Stock Split”); (ii) establish a new capital structure for the Company (the “New Capital Structure”); and (iii) effect a share exchange (the “Share Exchange”) (collectively, the “Recapitalization”). The Stock Split resulted in each one share owned by a stockholder being exchanged for three The Company’s Registration Statement on Form S-1 with the Securities and Exchange Commission (“SEC”) was declared effective on July 28, 2020, resulting in the Class A shares being registered and available for trading on the NASDAQ exchange (the “Offering”). On July 31, 2020, the Company received $423,024 in proceeds from the sale of 23,812 shares of Class A at a public offering price of $19.00 per share, net of underwriting fees, and used a portion of the proceeds to pay off $175,000 in outstanding debt. The net proceeds remaining after payment of Offering costs are being used for working capital and other corporate purposes.
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, 2021, 2020 and 2019 approximately 7%, 5% and 4%, respectively, of the Company’s revenues were generated outside of the U.S. As of December 31, 2021 and 2020, $699 and $287, 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, 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 subscription cancellations. 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, 2021, 2020 and 2019.
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) the reserve for self-insurance, (iv) assumptions related to achievement of technological feasibility for software developed for sale, (v) product life cycles, (vi) estimated useful lives and potential impairment of long-lived assets and intangible assets, (vii) potential impairment of goodwill, (viii) determination of the fair value of tangible and intangible assets acquired, liabilities assumed and consideration transferred in acquisitions, (ix) amortization period of material rights and deferred commissions (x) valuation of the Company’s stock used to measure stock-based compensation awards, (xi) Black-Scholes-Merton option pricing model (“Black-Scholes model”) input assumptions used to determine the fair value of stock-based compensation awards, (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 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. See Recently Adopted Accounting Pronouncements, Leases ​ ​ 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 ​
Internal-Use Software	Internal-Use Software The Company follows ASC 350-40, Goodwill and Other, Internal-Use Software,
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 future revenues, estimated economic life and changes in technology. Capitalized software includes direct labor and related expenses for software development for new products and enhancements to existing products and acquired software. 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 to five years. Unamortized capitalized software development costs determined to be in excess of the net realizable value of the product are expensed immediately. Capitalized software costs are subject to an ongoing assessment of recoverability based on anticipated future revenues and changes in software technologies at least annually at December 31, and whenever events or circumstances make it more likely than not that impairment may have occurred. 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 income (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 income (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 Accounting Standards Update (“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 On the effective date of the Offering, the Company adopted the 2020 Incentive Award Plan (the “2020 Plan”) and the 2020 Employee Stock Purchase Plan (the “ESPP”), which 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. SARs are accounted for as liabilities under ASC 718 and, as such, the Company recognizes stock-based compensation expense by remeasuring the value of the SARs at the end of each reporting period and accruing the portion of the requisite service rendered at that date. Prior to the date management determined the Company was considered to have become a public entity, the Company measured SARs at their intrinsic value. After such date, management remeasured outstanding SARs using the fair value-based method under ASC 718. Stock-based compensation expense for stock options issued under the 2020 Plan after the Offering 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. A total of 1,000 shares of Class A common were initially reserved for issuance under the ESPP. The number of shares available for issuance under the ESPP will be increased 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 common stock outstanding on the final day of the immediately preceding calendar year and (ii) such smaller number of shares as is determined by the board of directors (“Board”), provided that no more than 16,000 shares of Class A common stock may be issued. The ESPP is administered by a committee of the Board. As of December 31, 2021, there were 2,278 shares available for issuance under the ESPP. The ESPP permits participants to purchase Class A common stock through payroll deductions, up to a specified percentage of their eligible compensation, or for the initial offering period ended November 30, 2020, a lump sum contribution. 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 Effective January 1, 2021, the Company adopted ASU No. 2016-02, Leases 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 income (loss) on a straight-line basis over the lease term. For periods prior to the adoption of ASC 842, the Company recorded rent expense on a straight-line basis over the term of the related lease. The difference between the straight-line rent expense and the payments made in accordance with the operating lease agreements were recognized as a deferred rent liability within other liabilities on the accompanying consolidated balance sheets.
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 $1,922 and $1,766 at December 31, 2021 and 2020, 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 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 (collectively “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. Certain on-premise software subscription prices in the initial subscription year are higher than standard renewal prices. The excess initial year price over the renewal price (“new sale premium”) 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. 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. 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 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. 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 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 income (loss). These amounts were $14, $199, and $1,107 for the years ended December 31, 2021, 2020 and 2019, 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 income (loss). Total advertising expense was $20,386, $11,069, and $11,921 for the years ended December 31, 2021, 2020, and 2019, 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 stockholders' equity (deficit) 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 income (loss). Other operating expense, net in the consolidated statements of comprehensive income (loss) includes net foreign exchange transaction gains (losses) of $183, $(155), and $(84) for the years ended December 31, 2021, 2020 and 2019, respectively.
Income Taxes	Income Taxes On July 27, 2020, the Company’s S-Corporation election (the “S Election”) was terminated by the Company’s stockholders in connection with the Offering. As a result, Vertex will now be taxed at the corporate level as a C-Corporation for U.S federal and state income tax purposes. In connection with the S Election termination, the Company entered into an agreement with the S-Corporation stockholders pursuant to which the Company has 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 termination (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 have 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. Prior to July 27, 2020, as Vertex was taxed as an S-Corporation for U.S. federal income tax purposes and for most states, net income or loss was allocated to the stockholders and was included on their individual income tax returns. Historically the Company distributed amounts to the stockholders to satisfy their tax liabilities resulting from allocated net income or loss. In certain states, Vertex was taxed at the corporate level. Accordingly, the income tax provision or benefit was based on taxable income allocated to these states. In certain foreign jurisdictions, Vertex subsidiaries were taxed at the corporate level. Similar to states, the income tax provision or benefit is based on taxable income sourced to these foreign jurisdictions. Certain foreign subsidiaries in which the Company owns greater than 50% of the equity by measure of vote or value are treated as controlled foreign companies (“CFCs”) for U.S. federal income tax purposes and most states under the IRS foreign tax regulations. In conjunction with the termination of the S Election, certain direct and indirect wholly owned foreign subsidiaries that were previously treated as disregarded entities for U.S. federal income tax purposes and most states under the Internal Revenue Service (“IRS”) “check-the-box” regulations, “unchecked-the-box” to become regarded entities and as a result, became CFCs. Prior to these elections, the income and loss from these entities was reported on the Company’s U.S. federal and most state income tax returns in addition to being reported on a foreign jurisdiction tax return regardless of whether or not the earnings were repatriated. The Company records deferred income taxes using the liability method. The Company recognizes deferred tax assets and liabilities for future tax consequences of events that have been previously recognized in the Company’s consolidated financial statements and tax returns. The measurement of deferred tax assets and liabilities is based on provisions of the enacted tax law. 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 threshold, management recognizes the largest amount of tax benefit that is greater than 50 percent likely to be realized upon ultimate settlement with the related tax authority. 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. The Company recorded a deferred tax asset during the year ended December 31, 2020 as a result of the conversion from an S-Corporation to a C-Corporation. The deferred tax asset is primarily due to future stock-based compensation deductions for tax purposes resulting from SARs that were previously issued by the Company, converted to options and immediately exercised upon the effective date of the Offering. The exercise of these options has resulted in a net operating loss for the C-Corporation short tax year beginning July 27, 2020 and ending December 31, 2020. Based on Management’s evaluation of the positive and negative evidence, it is more likely than not that the Company will realize these benefits on future U.S. tax returns.
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.
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, 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 common stock equivalents. In periods of net loss available to common stockholders, diluted calculations are equal to basic calculations because the inclusion of common stock equivalents would be anti-dilutive. In accordance with ASC 260, Earnings Per Share
Supplemental Balance Sheet Information	Supplemental Balance Sheet Information Supplemental information for certain consolidated balance sheet accounts are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of Ended December 31, ​ 2021 2020 Prepaid expenses and other current assets: ​ ​ Prepaid expenses ​ $ 12,251 ​ $ 6,334 Prepaid licenses and support ​ ​ 8,285 ​ ​ 6,925 Prepaid expenses and other current assets ​ $ 20,536 ​ $ 13,259 ​ ​ ​ ​ ​ ​ ​ Accrued expenses: ​ ​ ​ ​ ​ ​ Accrued general expenses ​ $ 17,894 ​ $ 15,964 Accrued professional fees ​ ​ 2,565 ​ ​ 631 Accrued income and other taxes ​ ​ 2,507 ​ ​ 2,581 Accrued expenses ​ $ 22,966 ​ $ 19,176
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, ​ 2021 2020 2019 Cash paid for: ​ ​ ​ Interest ​ $ 223 ​ $ 2,461 ​ $ 1,766 Income taxes, net of refunds ​ ​ 1,287 ​ ​ 588 ​ ​ 945 Operating cash flows from operating leases ​ ​ 4,692 ​ ​ — ​ ​ — Non-cash investing and financing activities: ​ ​ ​ ​ ​ ​ Distributions payable ​ ​ — ​ ​ — ​ ​ 13,183 Estimated distributions payable under Tax Sharing Agreement ​ ​ 536 ​ ​ 2,700 ​ ​ — Purchase commitment and contingent consideration liabilities ​ ​ 12,736 ​ ​ 12,592 ​ ​ — Deferred purchase consideration ​ ​ 39,024 ​ ​ — ​ ​ — Remeasurement of options for redeemable shares ​ ​ — ​ ​ 51,833 ​ ​ 2,763 Conversion of SARs in connection with the Offering ​ ​ — ​ ​ 129,710 ​ ​ — Exchange of Amended Options in connection with the Offering ​ ​ — ​ ​ 69,177 ​ ​ — Exercised options exchanged in lieu of income taxes ​ ​ — ​ ​ — ​ ​ 184 Leased assets obtained in exchange for new finance lease liabilities ​ ​ 173 ​ ​ — ​ ​ — Equipment acquired through capital leases ​ ​ — ​ ​ 646 ​ ​ 1,904
Recently Issued and Recently Adopted Accounting Pronouncements	Recently Issued Accounting Pronouncements As an "emerging growth company," the Jumpstart Our Business Startups Act (the “JOBS Act”) allows the Company to delay adoption of new or revised accounting pronouncements applicable to public companies until such pronouncements are made applicable to private companies. The Company has elected to delay adoption of certain new or revised accounting standards. As a result, the Company’s consolidated financial statements may not be 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. Deferred Revenue In October 2021, the Financial Accounting Standard Board (“FASB”) issued ASU No. 2021-08, Business Combinations Recently Adopted Accounting Pronouncements Leases In February 2016, the FASB issued ASC 842. This standard amended several aspects of lease accounting, including requiring lessees to recognize operating leases with an initial term greater than one year on their balance sheet as a right-of-use asset, and a corresponding lease liability, measured at the present value of the future minimum lease payments. The standard is effective for public entities for fiscal years and interim periods beginning after December 15, 2018. For all other entities, the standard is effective for fiscal years beginning after December 15, 2021, including interim periods within those fiscal years. The Company adopted ASC 842 on January 1, 2021 using the modified retrospective transition method, which did not require the Company to adjust comparative periods. The Company’s lease assets and lease liabilities are recognized on the lease commencement date in an amount that represents the present value of future lease payments. The Company’s incremental borrowing rate, which is based on information available at the adoption date for existing leases and the commencement date for leases commencing after the adoption date, is used to determine the present value of lease payments. The Company elected the “package of three” practical expedients permitted under the transition guidance, which allows (i) a carry forward of the historical lease classification conclusions, (ii) management to assess whether a contract is or contains a lease, and (iii) the retention of initial direct costs for any leases that exist prior to adoption of the new standard. As a result of the adoption of ASC 842 on January 1, 2021, the Company recorded both operating lease right-of-use assets of $24,004 and operating lease liabilities of $32,562 in addition to writing off deferred rent of $9,554 amongst other adjustments. An adjustment to retained earnings of $508, net of the deferred tax impact, was also recorded. The adoption of ASC 842 had an immaterial impact on the consolidated statement of comprehensive income (loss) and the consolidated cash flow. The adoption of this standard also resulted in a change in the naming convention for leases classified historically as capital leases. These leases are now referred to as finance leases within property and equipment, with corresponding short-term and long-term debt liabilities being presented as “Current portion of finance lease liabilities” and “Finance lease liabilities, net of current portion,” respectively. See Note 7 for further information. Credit Losses In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326) Measurement of Credit Losses on Financial Instruments of an SEC filer (excluding smaller reporting companies), and after December 15, 2022 for all other entities. The Company adopted this standard effective January 1, 2021, and this guidance did not have a material impact on the Company’s consolidated financial statements. Income Taxes In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes,
Risks and Uncertainties	Risks and Uncertainties In March 2020, the World Health Organization declared the outbreak of coronavirus disease 2019 (“COVID-19”) to be a pandemic. The COVID-19 pandemic is continuing to have widespread, rapidly evolving and unpredictable impacts on global society, economies, financial markets and business practices. To protect the health and well-being of Company employees and customers, substantial modifications were made to employee travel policies, and our offices were closed, and remained closed through December 31, 2021, with employees directed to work from home. In addition, conferences and other marketing events were cancelled or shifted to virtual-only, and the Company continued to participate virtually through December 31, 2021. The COVID-19 pandemic has impacted, and may continue to impact, Company operations, including employees, customers and partners, and there is substantial uncertainty regarding the nature and degree of its continued effects over time. The Company did not experience any significant reductions in sales, revenues or collections through December 31, 2021 as a result of COVID-19. The uncertainty caused by the COVID-19 pandemic could, however, impact Company billings to new customers in 2022, and may also negatively impact Company efforts to expand revenues from existing customers as they continue to evaluate certain long-term projects and budget constraints. In addition to the potential impact on sales, the Company may see delays in collections during 2022 as customers continue to adjust their operating protocols to accommodate implementation of criteria to protect the health and well-being of their employees and customers. However, these delays are not expected to materially impact the business, and thus the Company has not recorded additional credit losses associated with the allowance for doubtful accounts in connection with any delays. The Company believes it has ample liquidity and capital resources to continue to meet its operating needs and to service debt and other financial obligations. The extent to which the COVID-19 pandemic impacts the business going forward will depend on numerous evolving factors that cannot reliably be predicted, including the duration and scope of the pandemic; governmental, business, and individuals’ actions in response to the pandemic; and the impact on economic activity, including the possibility of recession or financial market instability. These factors may adversely impact consumer, business and government spending on technology as well as customers’ ability to pay for Company products and services on an ongoing basis. This uncertainty also affects management’s accounting estimates and assumptions, which could result in greater variability in a variety of areas that depend on these estimates and assumptions.

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
	Dec. 31, 2021
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Schedule of accounting standards update	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As Reported ​ Revision ​ As Revised September 30, 2020 (unaudited) ​ ​ ​ ​ ​ ​ ​ Deferred income tax asset $ 32,440 ​ $ 3,856 $ 36,296 Total assets ​ ​ 514,934 ​ ​ 3,856 ​ 518,790 Retained earnings ​ ​ 21,696 ​ ​ 3,856 ​ ​ 25,552 Total stockholders' equity ​ ​ 218,561 ​ ​ 3,856 ​ 222,417 Total liabilities and stockholders' equity ​ ​ 514,934 ​ ​ 3,856 ​ 518,790 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ Deferred income tax asset $ 29,974 ​ $ 3,856 $ 33,830 Total assets ​ ​ 554,928 ​ ​ 3,856 ​ 558,784 Retained earnings ​ ​ 21,926 ​ ​ 3,856 ​ ​ 25,782 Total stockholders' equity ​ ​ 225,486 ​ ​ 3,856 ​ 229,342 Total liabilities and stockholders' equity ​ ​ 554,928 ​ ​ 3,856 ​ 558,784 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2021 (unaudited) ​ ​ ​ ​ ​ ​ ​ Deferred income tax asset $ 30,373 ​ $ 3,856 $ 34,229 Total assets ​ ​ 558,337 ​ ​ 3,856 ​ ​ 562,193 Retained earnings ​ ​ 24,722 ​ ​ 3,856 ​ ​ 28,578 Total stockholders' equity ​ ​ 226,576 ​ ​ 3,856 ​ ​ 230,432 Total liabilities and stockholders' equity ​ ​ 558,337 ​ ​ 3,856 ​ ​ 562,193 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, 2021 (unaudited) ​ ​ ​ ​ ​ ​ ​ Deferred income tax asset $ 32,573 ​ $ 3,856 $ 36,429 Total assets ​ ​ 609,529 ​ ​ 3,856 ​ ​ 613,385 Retained earnings ​ ​ 25,530 ​ ​ 3,856 ​ ​ 29,386 Total stockholders' equity ​ ​ 227,844 ​ ​ 3,856 ​ ​ 231,700 Total liabilities and stockholders' equity ​ ​ 609,529 ​ ​ 3,856 ​ ​ 613,385 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2021 (unaudited) ​ ​ ​ ​ ​ ​ ​ Deferred income tax asset $ 32,816 ​ $ 3,856 $ 36,672 Total assets ​ ​ 645,844 ​ ​ 3,856 ​ ​ 649,700 Retained earnings ​ ​ 21,582 ​ ​ 3,856 ​ ​ 25,438 Total stockholders' equity ​ ​ 224,211 ​ ​ 3,856 ​ ​ 228,067 Total liabilities and stockholders' equity ​ ​ 645,844 ​ ​ 3,856 ​ ​ 649,700 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended September 30, 2020 ​ Nine months ended September 30, 2020 (unaudited) As Reported ​ Revision ​ As Revised ​ As Reported ​ Revision ​ As Revised Income tax benefit $ (30,773) ​ $ (3,856) $ (34,629) ​ $ (31,508) ​ $ (3,856) $ (35,364) Net loss ​ ​ (21,028) ​ ​ 3,856 ​ ​ (17,172) ​ ​ (79,167) ​ ​ 3,856 ​ ​ (75,311) Total comprehensive loss ​ ​ (21,266) ​ ​ 3,856 ​ ​ (17,410) ​ ​ (82,679) ​ ​ 3,856 ​ ​ (78,823) Net loss attributable to Class A stockholders, basic ​ ​ (2,751) ​ ​ 505 ​ ​ (2,246) ​ ​ (2,427) ​ ​ 149 ​ ​ (2,278) Net loss per Class A share, basic ​ ​ (0.15) ​ ​ 0.03 ​ ​ (0.12) ​ ​ (0.40) ​ ​ 0.03 ​ ​ (0.37) Net loss attributable to Class A stockholders, diluted ​ ​ (2,751) ​ ​ 505 ​ ​ (2,246) ​ ​ (2,427) ​ ​ 149 ​ ​ (2,278) Net loss per Class A share, diluted ​ ​ (0.15) ​ ​ 0.03 ​ ​ (0.12) ​ ​ (0.40) ​ ​ 0.03 ​ ​ (0.37) Net loss attributable to Class B stockholders, basic ​ ​ (18,277) ​ ​ 3,351 ​ ​ (14,926) ​ ​ (76,740) ​ ​ 3,707 ​ ​ (73,033) Net loss per Class B share, basic ​ ​ (0.15) ​ ​ 0.03 ​ ​ (0.12) ​ ​ (0.64) ​ ​ 0.03 ​ ​ (0.61) Net loss attributable to Class B stockholders, diluted ​ ​ (18,277) ​ ​ 3,351 ​ ​ (14,926) ​ ​ (76,740) ​ ​ 3,707 ​ ​ (73,033) Net loss per Class B share, diluted ​ ​ (0.15) ​ ​ 0.03 ​ ​ (0.12) ​ ​ (0.64) ​ ​ 0.03 ​ ​ (0.61) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As Reported ​ Revision ​ As Revised Income tax benefit ​ ​ ​ ​ ​ ​ ​ ​ ​ $ (28,932) ​ $ (3,856) $ (32,788) Net loss ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (78,937) ​ ​ 3,856 ​ ​ (75,081) Total comprehensive loss ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (81,573) ​ ​ 3,856 ​ ​ (77,717) Net loss attributable to Class A stockholders, basic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (6,660) ​ ​ 325 ​ ​ (6,335) Net loss per Class A share, basic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (0.60) ​ ​ 0.03 ​ ​ (0.57) Net loss attributable to Class A stockholders, diluted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (6,660) ​ ​ 325 ​ ​ (6,335) Net loss per Class A share, diluted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (0.60) ​ ​ 0.03 ​ ​ (0.57) Net loss attributable to Class B stockholders, basic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (72,277) ​ ​ 3,531 ​ ​ (68,746) Net loss per Class B share, basic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (0.60) ​ ​ 0.03 ​ ​ (0.57) Net loss attributable to Class B stockholders, diluted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (72,277) ​ ​ 3,531 ​ ​ (68,746) Net loss per Class B share, diluted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (0.60) ​ ​ 0.03 ​ ​ (0.57) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine months ended September 30, 2020 (unaudited) As Reported ​ Revision ​ As Revised Net loss $ (79,167) ​ $ 3,856 $ (75,311) Deferred income tax benefit ​ ​ (32,004) ​ ​ (3,856) ​ ​ (35,860) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended December 31, 2020 ​ ​ As Reported ​ Revision ​ As Revised Net loss $ (78,937) ​ $ 3,856 $ (75,081) Deferred income tax benefit ​ ​ (29,643) ​ ​ (3,856) ​ ​ (33,499) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended September 30, 2020 (unaudited) ​ As Reported ​ Revision ​ As Revised Net loss ​ $ (21,028) ​ $ 3,856 ​ $ (17,172) Retained earnings ​ ​ 21,696 ​ ​ 3,856 ​ ​ 25,552 Total stockholders' equity ​ ​ 218,561 ​ ​ 3,856 ​ ​ 222,417 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended December 31, 2020 ​ ​ As Reported ​ Revision ​ As Revised Net loss ​ $ (78,937) ​ $ 3,856 ​ $ (75,081) Retained earnings ​ ​ 21,926 ​ ​ 3,856 ​ ​ 25,782 Total stockholders' equity ​ ​ 225,486 ​ ​ 3,856 ​ ​ 229,342 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended March 31, 2021 (unaudited) ​ As Reported ​ Revision ​ As Revised Retained earnings ​ $ 24,722 ​ $ 3,856 ​ $ 28,578 Total stockholders' equity ​ ​ 226,576 ​ ​ 3,856 ​ ​ 230,432 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three and six months ended June 30, 2021 (unaudited) As Reported ​ Revision ​ As Revised Retained earnings ​ $ 25,530 ​ $ 3,856 ​ $ 29,386 Total stockholders' equity ​ ​ 227,844 ​ ​ 3,856 ​ ​ 231,700 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three and nine months ended September 30, 2021 (unaudited) As Reported ​ Revision ​ As Revised Retained earnings ​ $ 21,582 ​ $ 3,856 ​ $ 25,438 Total stockholders' equity ​ ​ 224,211 ​ ​ 3,856 ​ ​ 228,067
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 supplemental balance sheet information	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of Ended December 31, ​ 2021 2020 Prepaid expenses and other current assets: ​ ​ Prepaid expenses ​ $ 12,251 ​ $ 6,334 Prepaid licenses and support ​ ​ 8,285 ​ ​ 6,925 Prepaid expenses and other current assets ​ $ 20,536 ​ $ 13,259 ​ ​ ​ ​ ​ ​ ​ Accrued expenses: ​ ​ ​ ​ ​ ​ Accrued general expenses ​ $ 17,894 ​ $ 15,964 Accrued professional fees ​ ​ 2,565 ​ ​ 631 Accrued income and other taxes ​ ​ 2,507 ​ ​ 2,581 Accrued expenses ​ $ 22,966 ​ $ 19,176
Schedule of supplemental cash flow disclosures	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Year Ended December 31, ​ 2021 2020 2019 Cash paid for: ​ ​ ​ Interest ​ $ 223 ​ $ 2,461 ​ $ 1,766 Income taxes, net of refunds ​ ​ 1,287 ​ ​ 588 ​ ​ 945 Operating cash flows from operating leases ​ ​ 4,692 ​ ​ — ​ ​ — Non-cash investing and financing activities: ​ ​ ​ ​ ​ ​ Distributions payable ​ ​ — ​ ​ — ​ ​ 13,183 Estimated distributions payable under Tax Sharing Agreement ​ ​ 536 ​ ​ 2,700 ​ ​ — Purchase commitment and contingent consideration liabilities ​ ​ 12,736 ​ ​ 12,592 ​ ​ — Deferred purchase consideration ​ ​ 39,024 ​ ​ — ​ ​ — Remeasurement of options for redeemable shares ​ ​ — ​ ​ 51,833 ​ ​ 2,763 Conversion of SARs in connection with the Offering ​ ​ — ​ ​ 129,710 ​ ​ — Exchange of Amended Options in connection with the Offering ​ ​ — ​ ​ 69,177 ​ ​ — Exercised options exchanged in lieu of income taxes ​ ​ — ​ ​ — ​ ​ 184 Leased assets obtained in exchange for new finance lease liabilities ​ ​ 173 ​ ​ — ​ ​ — Equipment acquired through capital leases ​ ​ — ​ ​ 646 ​ ​ 1,904

REVENUE RECOGNITION (Tables)

REVENUE RECOGNITION (Tables)	12 Months Ended
	Dec. 31, 2021
REVENUE RECOGNITION
Schedule of disaggregation of revenue	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Year Ended December 31, ​ ​ 2021 2020 2019 Software subscriptions: ​ ​ ​ ​ ​ ​ Software licenses ​ $ 231,371 ​ $ 229,744 ​ $ 223,116 Cloud subscriptions ​ ​ 127,044 ​ ​ 87,019 ​ ​ 52,513 Software subscriptions ​ ​ 358,415 ​ ​ 316,763 ​ ​ 275,629 Services ​ 67,133 ​ 57,902 ​ 45,871 Total revenues ​ $ 425,548 ​ $ 374,665 ​ $ 321,500
Schedule of beginning and ending balances of accounts receivable, net of allowance	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Year Ended December 31, ​ 2021 2020 Balance, beginning of period ​ $ 77,159 ​ $ 70,367 Balance, end of period ​ 76,929 ​ 77,159 Increase, net ​ $ (230) ​ $ 6,792
Schedule of beginning and ending balances of and changes to the allowance and the deferred allowance	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Year Ended December 31, ​ ​ 2021 ​ 2020 ​ 2019 ​ Balance ​ Net Change Balance ​ Net Change Balance ​ Net Change Allowance balance, January 1 ​ $ (8,592) ​ ​ $ (7,515) ​ ​ $ (5,527) ​ Allowance balance, December 31 ​ (9,151) ​ ​ (8,592) ​ ​ (7,515) ​ Change in allowance ​ ​ ​ $ 559 ​ ​ ​ $ 1,077 ​ ​ ​ $ 1,988 Deferred allowance balance, January 1 ​ 6,432 ​ ​ 5,614 ​ ​ 4,858 ​ Deferred allowance balance, December 31 ​ 6,537 ​ ​ 6,432 ​ ​ 5,614 ​ Change in deferred allowance ​ ​ ​ (105) ​ ​ ​ (818) ​ ​ ​ (756) Net amount charged to revenues ​ ​ ​ $ 454 ​ ​ ​ $ 259 ​ ​ ​ $ 1,232 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ ​ 2021 ​ 2020 Balances: ​ ​ Deferred revenue, current ​ $ 237,344 ​ $ 207,560 Deferred revenue, non-current ​ 11,666 ​ 14,702 Total deferred revenue ​ $ 249,010 ​ $ 222,262 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Year Ended December 31, ​ ​ 2021 ​ 2020 ​ 2019 Changes to deferred revenue: ​ ​ ​ Beginning balance ​ $ 222,262 ​ $ 205,791 ​ $ 178,703 Additional amounts deferred ​ 452,296 ​ 391,136 ​ 348,588 Revenues recognized ​ (425,548) ​ (374,665) ​ (321,500) Ending balance ​ $ 249,010 ​ $ 222,262 ​ $ 205,791
Schedule of information about the balances of and changes to deferred revenue	​ ​ ​ ​ ​ Year Ending December 31, ​ ​ 2022 ​ $ 237,344 2023 ​ 10,161 2024 ​ 1,505 Total ​ $ 249,010
Schedule of information about the changes to contract cost balances	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Year Ended December 31, ​ ​ 2021 ​ 2020 ​ 2019 Changes to deferred commissions: ​ ​ ​ Beginning balance ​ $ 11,743 ​ $ 11,196 ​ $ 8,830 Additions ​ 10,018 ​ 8,291 ​ 10,140 Amortization ​ (9,206) ​ (7,744) ​ (7,774) Ending balance ​ $ 12,555 ​ $ 11,743 ​ $ 11,196

BUSINESS COMBINATIONS (Tables)

BUSINESS COMBINATIONS (Tables)	12 Months Ended
	Dec. 31, 2021
LCR-Dixon
Business combinations
Schedule of purchase price	​ ​ ​ ​ ​ ​ ​ September 22, 2021 Cash paid at closing ​ $ 59,720 Fair value of deferred purchase consideration ​ ​ 39,024 Total ​ $ 98,744
Schedule of purchase price to assets acquired and liabilities assumed	​ ​ ​ ​ ​ ​ ​ September 22, 2021 Cash and cash equivalents ​ $ 1,899 Accounts receivable ​ ​ 1,437 Prepaid expenses and other current assets ​ ​ 326 Property and equipment ​ ​ 4 Goodwill ​ ​ 96,968 Accounts payable ​ ​ (19) Accrued expenses ​ ​ (306) Accrued compensation ​ ​ (1,746) Deferred revenue ​ ​ (71) Total ​ $ 98,492
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 income ​ ​ — 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 5) ​ $ 40,746 ​ Multi-period excess earnings method - income approach ​ 3 years ​ 16.5 % Trade name ​ Goodwill and other intangible assets (Note 8) ​ $ 608 ​ Relief from royalty method - income approach ​ 2 years ​ 16.5 % Customer relationships ​ Goodwill and other intangible assets (Note 8) ​ $ 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
Systax
Business combinations
Schedule of purchase price	​ ​ ​ ​ ​ ​ ​ January 7, 2020 Cash paid to Systax Quotaholders at closing ​ $ 11,626 Cash held in escrow for benefit of Systax Quotaholders ​ 748 Initial cash consideration ​ ​ 12,374 Purchase Commitment Liability ​ 12,592 Total ​ $ 24,966
Schedule of purchase price to assets acquired and liabilities assumed	​ ​ ​ ​ ​ ​ ​ January 7, 2020 Cash ​ $ 56 Accounts receivable ​ ​ 495 Property and equipment ​ 112 Other current assets ​ 14 Goodwill ​ 21,089 Other intangible assets ​ ​ 3,650 Accounts payable ​ (358) Accrued expenses ​ ​ (92) Total ​ $ 24,966

FINANCIAL INSTRUMENTS AND FAI_2

FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS (Tables)	12 Months Ended
	Dec. 31, 2021
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, 2021 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 ​ $ 10,703 ​ $ 10,703 ​ $ — ​ $ — ​ Tellutax Contingent Consideration ​ $ (2,500) ​ $ — ​ $ — ​ $ (2,500) ​ Foreign currency forward contracts ​ $ — ​ $ — ​ $ (62) ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements Using ​ As of December 31, 2020 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 ​ $ 265,270 ​ $ 265,270 ​ $ — ​ $ — ​ Tellutax Contingent Consideration ​ $ — ​ $ — ​ $ — ​ $ — ​ Foreign currency forward contracts ​ $ — ​ $ — ​ $ 448 ​ $ — ​
Summary of estimated fair value of tellutax contingent consideration	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 Liability Fair Value Valuation Technique Unobservable Inputs Tellutax Contingent Consideration ​ $ (2,500) ​ Monte Carlo Simulation ​ Revenue volatility ​ 95.0 % ​ ​ ​ ​ ​ ​ ​ Revenue discount rate ​ 20.0 % ​ ​ ​ ​ ​ ​ ​ Term (in years) ​ 3.6 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ January 25, 2021 Liability Fair Value Valuation Technique Unobservable Inputs Tellutax Contingent Consideration ​ $ (2,200) ​ Monte Carlo Simulation ​ Revenue volatility ​ 95.0 % ​ ​ ​ ​ ​ ​ ​ Revenue discount rate ​ 20.3 % ​ ​ ​ ​ ​ ​ ​ Term (in years) ​ 4.3 ​
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)

PROPERTY AND EQUIPMENT (Tables)

PROPERTY AND EQUIPMENT (Tables)	12 Months Ended
	Dec. 31, 2021
PROPERTY AND EQUIPMENT
Schedule of major components of property and equipment	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ ​ 2021 ​ 2020 Leasehold improvements ​ $ 20,956 ​ $ 20,907 Equipment ​ 41,937 ​ 41,410 Computer software purchased ​ 11,792 ​ 11,620 Internal-use software developed: ​ ​ ​ ​ Cloud-based customer solutions ​ 114,872 ​ 65,423 Internal systems and tools ​ 32,408 ​ 25,349 Furniture and fixtures ​ 7,675 ​ 7,674 In-process internal-use software ​ 16,965 ​ 3,304 ​ ​ 246,605 ​ 175,687 Less accumulated depreciation ​ (148,215) ​ (119,130) Property and equipment, net ​ $ 98,390 ​ $ 56,557
Schedule of major components of internal-use software	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ ​ 2021 ​ 2020 Internal-use software developed ​ $ 147,280 ​ $ 90,772 Less accumulated depreciation ​ (87,281) ​ (65,090) ​ ​ 59,999 ​ 25,682 In-process internal-use software ​ 16,965 ​ 3,304 Internal-use software developed, net ​ $ 76,964 ​ $ 28,986
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, ​ ​ 2021 ​ 2020 ​ 2019 Cloud-based customer solutions $ 19,837 $ 14,710 $ 10,179 Internal systems and tools ​ 11,491 ​ 3,176 ​ 4,860 Total ​ $ 31,328 ​ $ 17,886 ​ $ 15,039
Schedule of amortization expense internally developed software	​ ​ ​ ​ ​ ​ ​ ​ Year Ending December 31, Internal Systems and Tools Cloud-Based Customer Solutions 2022 ​ $ 3,861 ​ $ 24,740 2023 ​ 2,831 ​ 19,624 2024 ​ 1,988 ​ 5,988 2025 ​ 845 ​ — 2026 ​ 122 ​ — Total ​ $ 9,647 ​ $ 50,352

CAPITALIZED SOFTWARE (Tables)

CAPITALIZED SOFTWARE (Tables)	12 Months Ended
	Dec. 31, 2021
CAPITALIZED SOFTWARE
Schedule of major components of capitalized software	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ 2021 2020 Capitalized software ​ $ 72,512 ​ $ 63,071 Less accumulated amortization ​ (45,179) ​ (32,217) ​ ​ 27,333 ​ 30,854 In-process capitalized software ​ 6,109 ​ 1,135 Capitalized software, net ​ $ 33,442 ​ $ 31,989
Schedule of in process capitalized software not available for general release	​ ​ ​ ​ ​ Year Ending December 31, ​ 2022 ​ $ 11,352 2023 ​ 8,514 2024 ​ 5,802 2025 ​ 1,416 2026 ​ 249 Total ​ $ 27,333

LEASES (Tables)

LEASES (Tables)	12 Months Ended
	Dec. 31, 2021
LEASES
Schedule of company's lease assets and lease liabilities and their balance sheet location	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ Balance Sheet Location 2021 Lease assets: ​ ​ ​ ​ Operating lease right-of-use assets ​ Operating lease right-of-use assets ​ $ 20,249 Finance lease assets ​ Property and equipment, net (Note 5) ​ ​ 602 Total lease assets ​ ​ ​ $ 20,851 ​ ​ ​ ​ ​ ​ Lease liabilities: ​ ​ ​ ​ ​ Current: ​ ​ ​ ​ ​ Operating lease liabilities ​ Current portion of operating lease liabilities ​ $ 3,933 Finance lease liabilities ​ Current portion of finance lease liabilities ​ ​ 284 Total current lease liabilities ​ ​ ​ ​ 4,217 Non-current: ​ ​ ​ ​ ​ Operating lease liabilities ​ Operating lease liabilities, net of current portion ​ ​ 24,320 Finance lease liabilities ​ Finance lease liabilities, net of current portion ​ ​ 68 Total non-current lease liabilities ​ ​ ​ ​ 24,388 Total lease liabilities ​ ​ ​ $ 28,605
Schedule of company's lease costs, weighted-average term and rate	​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2021 Operating lease cost ​ $ 4,774 ​ ​ ​ ​ Finance lease cost: ​ ​ ​ Amortization of lease assets ​ ​ 931 Interest on lease liabilities ​ ​ 16 Total lease cost ​ $ 5,721 ​ ​ ​ ​ ​ As of December 31, ​ ​ 2021 ​ Weighted-average remaining lease term (years): ​ ​ Operating leases 6.6 ​ Finance leases 1.2 ​ ​ ​ ​ Weighted-average discount rate: ​ ​ Operating leases 2.3 % Finance leases 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, 2021: ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating Leases Finance Leases 2022 ​ $ 4,593 ​ $ 289 2023 ​ ​ 4,459 ​ ​ 59 2024 ​ ​ 4,464 ​ ​ 10 2025 ​ ​ 4,382 ​ ​ — 2026 ​ ​ 4,477 ​ ​ — Thereafter ​ ​ 8,054 ​ ​ — Total lease payments ​ ​ 30,429 ​ ​ 358 Less: Imputed interest ​ ​ (2,176) ​ ​ (6) Present value of lease liabilities ​ $ 28,253 ​ $ 352
Schedule of maturity of finance lease liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ Operating Leases Finance Leases 2022 ​ $ 4,593 ​ $ 289 2023 ​ ​ 4,459 ​ ​ 59 2024 ​ ​ 4,464 ​ ​ 10 2025 ​ ​ 4,382 ​ ​ — 2026 ​ ​ 4,477 ​ ​ — Thereafter ​ ​ 8,054 ​ ​ — Total lease payments ​ ​ 30,429 ​ ​ 358 Less: Imputed interest ​ ​ (2,176) ​ ​ (6) Present value of lease liabilities ​ $ 28,253 ​ $ 352
Schedule of maturity of operating leases under ASU 840	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2020 ​ ​ Operating Leases ​ Capital Leases 2021 ​ $ 5,442 ​ $ 915 2022 ​ 4,518 ​ 230 2023 ​ 4,459 ​ — 2024 ​ 4,464 ​ — 2025 ​ 4,382 ​ — Thereafter ​ 12,531 ​ — Total lease payments ​ $ 35,796 ​ ​ 1,145 Less amount representing interest ​ ​ ​ ​ ​ (38) Present value of minimum lease payments ​ ​ ​ ​ ​ 1,107 Less current portion ​ ​ ​ ​ ​ (882) Capital lease obligations, net of current portion ​ ​ ​ ​ $ 225
Schedule of maturity of capital leases under ASU 840	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2020 ​ ​ Operating Leases ​ Capital Leases 2021 ​ $ 5,442 ​ $ 915 2022 ​ 4,518 ​ 230 2023 ​ 4,459 ​ — 2024 ​ 4,464 ​ — 2025 ​ 4,382 ​ — Thereafter ​ 12,531 ​ — Total lease payments ​ $ 35,796 ​ ​ 1,145 Less amount representing interest ​ ​ ​ ​ ​ (38) Present value of minimum lease payments ​ ​ ​ ​ ​ 1,107 Less current portion ​ ​ ​ ​ ​ (882) Capital lease obligations, net of current portion ​ ​ ​ ​ $ 225

GOODWILL AND OTHER INTANGIBLE_2

GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)	12 Months Ended
	Dec. 31, 2021
GOODWILL AND OTHER INTANGIBLE ASSETS
Changes in the carrying amount of goodwill	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ ​ 2021 ​ 2020 Goodwill ​ $ 270,041 ​ $ 16,329 Other intangible assets, net ​ ​ 2,661 ​ 2,382 Total ​ $ 272,702 ​ $ 18,711 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ ​ 2021 ​ 2020 Balance, January 1 ​ $ 16,329 ​ $ — Acquisitions ​ ​ 265,867 ​ 21,089 Foreign currency translation adjustments ​ ​ (12,155) ​ ​ (4,760) Balance, December 31, gross ​ ​ 270,041 ​ ​ 16,329 Accumulated impairment losses ​ ​ — ​ ​ — Balance, December 31, net ​ $ 270,041 ​ $ 16,329
Schedule of other acquired intangible assets	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31 ​ ​ ​ ​ ​ 2021 ​ 2020 Weighted average amortization period (years) ​ ​ ​ ​ ​ 4.2 ​ ​ 5.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross value ​ ​ ​ ​ $ 4,110 ​ $ 2,825 Accumulated amortization ​ ​ ​ ​ ​ (1,449) ​ ​ (443) Carrying value ​ ​ ​ ​ $ 2,661 ​ $ 2,382
Schedule of acquired intangible assets	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ending December 31, ​ Cost of Revenues, Software Subscriptions ​ Selling and Marketing Expense ​ Total Expense 2021 ​ $ 253 $ 813 $ 1,066 2020 ​ $ 267 $ 176 $ 443
Schedule of future amortization expense	​ ​ ​ ​ ​ Year Ending December 31, ​ 2022 ​ $ 1,203 2023 ​ 743 2024 ​ 466 2025 ​ 249 Total ​ $ 2,661

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	12 Months Ended
	Dec. 31, 2021
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: 2021 2020 2019 Numerator, basic: ​ ​ ​ ​ Net income (loss) attributable to all stockholders ​ $ (1,479) ​ $ (75,081) ​ $ 31,057 ​ Class A common stock as a percentage of total shares outstanding, basic ​ 24.12 % 8.44 % 0.08 % Net income (loss) attributable to Class A stockholders, basic ​ $ (357) ​ $ (6,335) ​ $ 23 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Numerator, diluted: ​ ​ ​ ​ Net income (loss) attributable to all stockholders ​ $ (1,479) ​ $ (75,081) ​ $ 31,057 ​ Class A common stock as a percentage of total shares outstanding, diluted ​ 24.12 % 8.44 % 3.11 % Net income (loss) attributable to Class A stockholders, diluted ​ $ (357) ​ $ (6,335) ​ $ 965 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Denominator, basic and diluted: ​ ​ ​ ​ Weighted average Class A common stock, basic ​ 35,647 ​ 11,096 ​ 118 ​ Dilutive effect of common stock equivalents (1), (2) ​ — ​ — ​ 3,743 ​ Weighted average Class A common stock, diluted ​ 35,647 ​ 11,096 ​ 3,861 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income (loss) per Class A share, basic ​ $ (0.01) ​ $ (0.57) ​ $ 0.20 ​ Net income (loss) per Class A share, diluted ​ $ (0.01) ​ $ (0.57) ​ $ 0.25 ​ 1 . ​ 2 .
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: 2021 ​ 2020 2019 Numerator, basic: ​ ​ ​ ​ Net income (loss) attributable to all stockholders ​ $ (1,479) ​ $ (75,081) ​ $ 31,057 ​ Class B common stock as a percentage of total shares outstanding, basic ​ 75.88 % 91.56 % 99.92 % Net income (loss) attributable to Class B stockholders, basic ​ $ (1,122) ​ $ (68,746) ​ $ 31,034 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Numerator, diluted: ​ ​ ​ ​ Net income (loss) attributable to all stockholders ​ $ (1,479) ​ $ (75,081) ​ $ 31,057 ​ Class B common stock as a percentage of total shares outstanding, diluted ​ 75.88 % 91.56 % 96.89 % Net income (loss) attributable to Class B stockholders, diluted ​ $ (1,122) ​ $ (68,746) ​ $ 30,092 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Denominator, basic and diluted: ​ ​ ​ ​ Weighted average Class B common stock, basic ​ 112,133 ​ 120,415 ​ 120,417 ​ Dilutive effect of common stock equivalents ​ — ​ — ​ — ​ Weighted average Class B common stock, diluted ​ 112,133 ​ 120,415 ​ 120,417 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income (loss) per Class B share, basic ​ $ (0.01) ​ $ (0.57) ​ $ 0.26 ​ Net income (loss) per Class B share, diluted ​ $ (0.01) ​ $ (0.57) ​ $ 0.25 ​

EMPLOYEE BENEFIT AND DEFERRED_2

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS (Tables)	12 Months Ended
	Dec. 31, 2021
Compensation plans:
Schedule of stock appreciation rights activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Units Range of ​ Vested Nonvested Total Grant Values Outstanding at January 1, 2019 5,889 4,782 10,671 ​ $ 0.92–$3.17 Granted 297 2,112 2,409 ​ $ 3.73 Exercised (609) — (609) ​ $ 1.31–$2.50 Forfeited — (195) (195) ​ $ 2.13–$2.50 Vested 630 (630) — ​ Outstanding at December 31, 2019 6,207 6,069 12,276 ​ $ 0.92–$3.73 Granted 21 681 702 ​ $ 4.70 Exercised (877) — (877) ​ $ 1.31–$2.50 Forfeited — (63) (63) ​ $ 2.50 Vested 1,410 (1,410) — ​ Converted (6,761) (5,277) (12,038) ​ $ 0.92–$4.70 Outstanding at December 31, 2020 — — — ​ ​ ​
Schedule of valuation assumptions	​ ​ ​ ​ ​ ​ Fair market value of common stock ​ $ 19.00 ​ Volatility 36.7 % Expected term (years) 6.5 ​ Expected dividend yield — % Risk-free interest rate 0.4 %
Schedule of ESPP valuation assumptions	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Offering Period Ending ​ ​ 11/30/2020 ​ 5/31/2021 ​ 11/30/2021 ​ 5/31/2022 Fair market value of common stock $ 19.00 ​ ​ $ 25.83 ​ ​ $ 18.89 ​ ​ $ 17.38 ​ Volatility ​ 35.0 % ​ 35.1 % ​ 35.1 % ​ 37.3 % Expected term (years) ​ 0.3 ​ ​ 0.5 ​ ​ 0.5 ​ ​ 0.5 ​ Expected dividend yield ​ - % ​ - % ​ - % ​ - % Risk-free interest rate ​ 0.1 % ​ 0.1 % ​ 0.1 % ​ 0.1 %
Schedule of stock-based compensation cost related to incentive awards	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Year Ended December 31, ​ 2021 2020 2019 Stock-based compensation expense: ​ ​ ​ SARs and Converted SARs ​ $ 16,023 ​ $ 143,123 ​ $ 9,460 Stock options ​ 1,510 ​ — ​ — RSUs ​ 2,964 ​ 171 ​ — RSAs ​ ​ 5,126 ​ ​ 4,284 ​ ​ — ESPP ​ 537 ​ 326 ​ — Total stock-based compensation expense ​ $ 26,160 ​ $ 147,904 ​ $ 9,460
Schedule of stock based compensation cost in consolidated statement of operations	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Year Ended December 31, ​ 2021 2020 2019 Stock-based compensation expense: ​ ​ ​ ​ ​ ​ ​ ​ ​ Cost of revenues, software subscriptions ​ $ 2,336 ​ $ 14,663 $ 946 Cost of revenues, services ​ 2,648 ​ 21,472 1,419 Research and development ​ 2,620 ​ 14,694 946 Selling and marketing ​ 6,371 ​ 29,551 1,892 General and administrative ​ 12,185 ​ 67,524 4,257 Total stock-based compensation expense ​ $ 26,160 ​ $ 147,904 ​ $ 9,460
Amended Options
Compensation plans:
Schedule of Option activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ Average ​ ​ ​ ​ ​ ​ ​ Average ​ Remaining ​ Aggregate ​ ​ ​ ​ ​ Exercise ​ Contractual ​ Intrinsic Amended Option Activity ​ Units ​ ​ Price ​ Life (Years) ​ Value Outstanding at January 1, 2019 ​ 4,125 ​ $ 0.20 ​ * ​ $ 14,581 Exercised ​ (276) ​ $ 0.25 ​ ​ ​ $ 957 Outstanding at December 31, 2019 ​ 3,849 ​ $ 0.19 ​ * ​ $ 17,344 Exercised through June 30 ​ (173) ​ $ 0.30 ​ ​ ​ $ 759 Amendment and exchange of options ​ (3,676) ​ $ 0.19 ​ * ​ $ 69,177 Outstanding at December 31, 2020 ​ — ​ ​ ​ ​ ​ ​ ​ ​ *Options have indefinite contractual lives ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
2020 Plan
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, 2020 ​ — ​ ​ — ​ ​ ​ ​ ​ Issued in connection with Converted SARs ​ 12,038 ​ $ 2.76 ​ ​ ​ ​ ​ Issued in connection with Amended Options ​ 3,676 ​ $ 0.19 ​ * ​ ​ ​ Total options granted ​ 15,714 ​ $ 2.16 ​ ​ ​ ​ ​ Forfeited ​ (156) ​ $ 3.29 ​ ​ ​ ​ ​ Exercised ​ (3,682) ​ $ 1.21 ​ ​ ​ ​ ​ 2020 Plan options outstanding at December 31, 2020 ​ 11,876 ​ $ 2.44 ​ 5.3 ​ $ 384,883 Granted ​ 779 ​ $ 23.06 ​ ​ ​ ​ ​ Forfeited ​ (292) ​ $ 4.06 ​ ​ ​ ​ ​ Exercised ​ (2,863) ​ $ 2.04 ​ ​ ​ ​ ​ 2020 Plan options outstanding at December 31, 2021 ​ 9,500 ​ $ 4.20 ​ 5.2 ​ $ 110,843 2020 Plan options exercisable at December 31, 2021 6,169 ​ $ 2.39 3.9 ​ $ 83,188 *Amended Options have indefinite contractual lives ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
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 1,854 — 1,854 — $2.15 462 3.1 462 3.1 $2.50 2,186 4.5 2,186 4.5 $2.67 419 5.2 42 5.1 $3.17 1,196 6.3 446 6.3 $3.73 ​ 1,932 ​ 7.8 ​ 1,061 ​ 7.8 $4.70 ​ 683 ​ 8.1 ​ — ​ — $18.47 ​ 213 ​ 9.9 ​ — ​ — $18.96 ​ 235 ​ 9.6 ​ 105 ​ 9.6 $19.00 69 9.7 — — $32.16 251 9.2 13 9.2 ​ 9,500 ​ ​ 6,169 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Schedule of valuation assumptions	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Option Valuation Period ​ ​ Q1 2021 ​ Q2 2021 ​ Q3 2021 Q3 2021 ​ ​ Q4 2021 ​ Fair market value of common stock ​ $ 32.16 ​ ​ $ 17.66 ​ ​ $ 18.96 ​ $ 19.00 ​ ​ $ 18.47 ​ Volatility 36.8 % ​ 36.8 % ​ 37.1 % ​ 37.1 % ​ 37.4 % Expected term (years) 6.0 ​ ​ 6.0 ​ ​ 5.0 ​ ​ 5.0 ​ ​ 5.0 ​ Expected dividend yield — % ​ — % ​ — % ​ — % ​ — % Risk-free interest rate 0.4 % ​ 0.4 % ​ 0.8 % ​ 0.9 % ​ 1.3 %
Restricted Stock Units
Compensation plans:
Schedule of restricted activity	​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ ​ ​ Grant Date Fair ​ ​ Units ​ Value Per Share Outstanding at January 1, 2020 — ​ ​ ​ Granted 101 ​ $ 23.80 Total at December 31, 2020 ​ 101 ​ ​ 23.80 Granted ​ 478 ​ ​ 27.07 Vested (15) ​ ​ 29.67 Forfeited (34) ​ ​ 25.18 Outstanding at December 31, 2021 ​ 530 ​ $ 26.49
Restricted Stock Awards
Compensation plans:
Schedule of restricted activity	​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ ​ ​ Grant Date Fair ​ ​ Units ​ Value Per Share Outstanding at January 1, 2020 — ​ ​ ​ Granted 694 ​ $ 19.00 Vested (21) ​ 19.00 Forfeited (3) ​ 19.00 Outstanding at December 31, 2020 ​ 670 ​ ​ 19.00 Granted ​ 59 ​ ​ 17.66 Vested ​ (363) ​ ​ 19.00 Forfeited ​ (40) ​ ​ 19.00 Outstanding at December 31, 2021 326 ​ $ 18.76

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2021
INCOME TAXES
Schedule of components of net income (loss) before income taxes	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Year Ended December 31, ​ ​ 2021 2020 2019 U.S. ​ $ 5,608 ​ $ (107,959) ​ $ 32,131 Foreign ​ (9,534) ​ 90 ​ (1,229) Net income (loss) before income taxes ​ $ (3,926) ​ $ (107,869) ​ $ 30,902
Schedule of Income tax benefit (expense)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Year Ended December 31, ​ ​ 2021 2020 2019 Current income taxes: ​ ​ ​ Federal ​ $ — ​ $ — ​ $ — State and local ​ ​ 155 ​ ​ 617 ​ ​ 578 Foreign ​ 468 ​ 94 ​ 115 Total current ​ 623 ​ 711 ​ 693 Deferred income taxes: ​ ​ ​ Federal ​ ​ (1,849) ​ ​ (27,076) ​ ​ — State and local ​ (7) ​ (6,491) ​ (677) Foreign ​ (1,214) ​ 68 ​ (171) Total deferred ​ (3,070) ​ (33,499) ​ (848) Income tax benefit ​ $ (2,447) ​ $ (32,788) ​ $ (155)
Schedule of reconciliation of the effective tax rate to tax	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 2020 2019 ​ ​ Total ​ Tax Rate ​ Total ​ Tax Rate Total ​ Tax Rate Pretax net (loss) income ​ $ (3,926) ​ $ (107,869) ​ $ 30,902 ​ Taxes: ​ ​ ​ ​ U.S. federal income tax at statutory rate ​ $ (825) 21.0 % $ (22,652) 21.0 % $ 6,489 21.0 % State income taxes ​ ​ 678 (17.3) % ​ (1,811) 1.7 % ​ (98) (0.3) % Tax effect of S-Corporation status ​ ​ — ​ — % ​ 21,325 ​ (19.8) % ​ (6,489) ​ (21.0) % Impact of change in tax status ​ ​ — ​ — % ​ (25,396) ​ 23.5 % ​ — ​ — % Stock-based compensation expense ​ ​ (4,550) ​ 115.9 % ​ (5,809) ​ 5.4 % ​ — ​ — % Impact of foreign operations ​ 954 ​ (24.3) % (56) ​ 0.1 % (57) (0.2) % Return to provision adjustments ​ ​ (464) ​ 11.8 % ​ — ​ — % ​ — ​ — % Transaction costs ​ ​ 1,082 ​ (27.6) % ​ — ​ — % ​ — ​ — % US taxation of foreign earnings ​ ​ 144 ​ (3.7) % ​ 81 ​ (0.1) % ​ — ​ — % Nondeductible compensation ​ ​ 682 ​ (17.4) % ​ 883 ​ (0.8) % ​ — ​ — % Tax credits ​ ​ (488) ​ 12.4 % ​ (44) ​ 0.0 % ​ — ​ — % Change in valuation allowance ​ ​ 373 ​ (9.5) % ​ 109 ​ (0.1) % ​ — ​ — % Profit sharing deduction ​ ​ (46) ​ 1.2 % ​ — ​ — % ​ — ​ — % Other permanent items, net ​ ​ 13 (0.2) % ​ 582 (0.5) % ​ — ​ — % Taxes and effective tax rate ​ $ (2,447) 62.3 % $ (32,788) 30.4 % $ (155) (0.5) %
Schedule of significant components of the Company's net deferred tax assets (liabilities)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, Deferred tax assets: 2021 2020 Deferred revenue ​ $ 3,788 ​ $ 3,189 State operating loss carry forwards ​ 3,894 ​ 2,595 Federal and foreign loss carry forwards ​ 21,617 ​ 13,388 Accrued expenses ​ 2,023 ​ 2,324 Accrued variable compensation ​ 3,110 ​ 3,414 Deferred and stock-based compensation ​ 24,971 ​ 29,188 Operating lease liabilities ​ ​ 7,204 ​ ​ 2,429 Tax credits ​ ​ 532 ​ ​ 44 Other ​ 53 ​ 303 Deferred tax assets ​ 67,192 ​ 56,874 Valuation allowance ​ (1,839) ​ (1,507) Total deferred tax assets ​ 65,353 ​ 55,367 Deferred tax liabilities: ​ ​ Depreciation and amortization ​ (26,269) ​ (19,998) Prepaid expenses ​ ​ (1,329) ​ ​ (1,557) Right of use asset ​ (5,120) ​ — Total deferred tax liabilities ​ (32,718) ​ (21,555) Net deferred tax asset ​ $ 32,635 ​ $ 33,812 ​ ​ ​ ​ ​ ​ ​ Classification in the consolidated balance sheets: ​ ​ ​ ​ ​ ​ Deferred income tax asset ​ $ 35,298 ​ $ 33,830 Deferred other liabilities ​ ​ (2,663) ​ ​ (18) Net deferred tax asset ​ $ 32,635 ​ $ 33,812

SUMMARY OF SIGNIFICANT ACCOUN_4

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)itemsegment	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Accounting policies:
Self-insurance accruals	$ 1,922	$ 1,766
Reporting units | item	1
Operating segments | segment	1
Reimbursable costs	$ 14	199	$ 1,107
Advertising expense	$ 20,386	$ 11,069	$ 11,921
Systax - VIE
Accounting policies:
Ownership (as a percent)	65.00%

SUMMARY OF SIGNIFICANT ACCOUN_5

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revision (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred income tax asset	$ 36,296	$ 36,296	$ 35,298	$ 33,830		$ 36,672	$ 36,429	$ 34,229
Total assets	518,790	518,790	670,207	558,784		649,700	613,385	562,193
Retained earnings	25,552	25,552	24,811	25,782		25,438	29,386	28,578
Total stockholders' equity	222,417	222,417	230,084	229,342		228,067	231,700	230,432
Total liabilities and stockholders' equity	518,790	518,790	670,207	558,784		649,700	613,385	562,193
Income tax benefit	(34,629)	(35,364)	(2,447)	(32,788)	$ (155)
Net income (loss)	(17,172)	(75,311)	(1,479)	(75,081)	31,057
Total comprehensive loss	(17,410)	(78,823)	(15,849)	(77,717)	31,062
Net income (loss)		(75,311)	(1,479)	(75,081)	31,057
Deferred income tax benefit		(35,860)	(3,116)	(33,499)	(848)
Class A
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net income (loss) attributable to stockholders, basic	$ (2,246)	$ (2,278)	$ (357)	$ (6,335)	$ 23
Net income (loss) per share, basic (in dollars per share)	$ (0.12)	$ (0.37)	$ (0.01)	$ (0.57)	$ 0.20
Net income (loss) attributable to stockholders, diluted	$ (2,246)	$ (2,278)	$ (357)	$ (6,335)	$ 965
Net income (loss) per share, diluted (in dollars per share)	$ (0.12)	$ (0.37)	$ (0.01)	$ (0.57)	$ 0.25
Class B
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net income (loss) attributable to stockholders, basic	$ (14,926)	$ (73,033)	$ (1,122)	$ (68,746)	$ 31,034
Net income (loss) per share, basic (in dollars per share)	$ (0.12)	$ (0.61)	$ (0.01)	$ (0.57)	$ 0.26
Net income (loss) attributable to stockholders, diluted	$ (14,926)	$ (73,033)	$ (1,122)	$ (68,746)	$ 30,092
Net income (loss) per share, diluted (in dollars per share)	$ (0.12)	$ (0.61)	$ (0.01)	$ (0.57)	$ 0.25
Accounting Changes and error corrections | As Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred income tax asset	$ 32,440	$ 32,440		$ 29,974		32,816	32,573	30,373
Total assets	514,934	514,934		554,928		645,844	609,529	558,337
Retained earnings	21,696	21,696		21,926		21,582	25,530	24,722
Total stockholders' equity	218,561	218,561		225,486		224,211	227,844	226,576
Total liabilities and stockholders' equity	514,934	514,934		554,928		645,844	609,529	558,337
Income tax benefit	(30,773)	(31,508)		(28,932)
Net income (loss)	(21,028)	(79,167)		(78,937)
Total comprehensive loss	(21,266)	(82,679)		(81,573)
Net income (loss)		(79,167)		(78,937)
Deferred income tax benefit		(32,004)		(29,643)
Accounting Changes and error corrections | Revision
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred income tax asset	3,856	3,856		3,856		3,856	3,856	3,856
Total assets	3,856	3,856		3,856		3,856	3,856	3,856
Retained earnings	3,856	3,856		3,856		3,856	3,856	3,856
Total stockholders' equity	3,856	3,856		3,856		3,856	3,856	3,856
Total liabilities and stockholders' equity	3,856	3,856		3,856		$ 3,856	$ 3,856	$ 3,856
Income tax benefit	(3,856)	(3,856)		(3,856)
Net income (loss)	3,856	3,856		3,856
Total comprehensive loss	3,856	3,856		3,856
Net income (loss)		3,856		3,856
Deferred income tax benefit	(3,856)	(3,856)		(3,856)
Accounting Changes and error corrections | Class A | As Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net income (loss) attributable to stockholders, basic	$ (2,751)	$ (2,427)		$ (6,660)
Net income (loss) per share, basic (in dollars per share)	$ (0.15)	$ (0.40)		$ (0.60)
Net income (loss) attributable to stockholders, diluted	$ (2,751)	$ (2,427)		$ (6,660)
Net income (loss) per share, diluted (in dollars per share)	$ (0.15)	$ (0.40)		$ (0.60)
Accounting Changes and error corrections | Class A | Revision
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net income (loss) attributable to stockholders, basic	$ 505	$ 149		$ 325
Net income (loss) per share, basic (in dollars per share)	$ 0.03	$ 0.03		$ 0.03
Net income (loss) attributable to stockholders, diluted	$ 505	$ 149		$ 325
Net income (loss) per share, diluted (in dollars per share)	$ 0.03	$ 0.03		$ 0.03
Accounting Changes and error corrections | Class B | As Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net income (loss) attributable to stockholders, basic	$ (18,277)	$ (76,740)		$ (72,277)
Net income (loss) per share, basic (in dollars per share)	$ (0.15)	$ (0.64)		$ (0.60)
Net income (loss) attributable to stockholders, diluted	$ (18,277)	$ (76,740)		$ (72,277)
Net income (loss) per share, diluted (in dollars per share)	$ (0.15)	$ (0.64)		$ (0.60)
Accounting Changes and error corrections | Class B | Revision
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net income (loss) attributable to stockholders, basic	$ 3,351	$ 3,707		$ 3,531
Net income (loss) per share, basic (in dollars per share)	$ 0.03	$ 0.03		$ 0.03
Net income (loss) attributable to stockholders, diluted	$ 3,351	$ 3,707		$ 3,531
Net income (loss) per share, diluted (in dollars per share)	$ 0.03	$ 0.03		$ 0.03

SUMMARY OF SIGNIFICANT ACCOUN_6

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Concentration of Credit Risk (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)item	Dec. 31, 2020USD ($)	Dec. 31, 2019
Segment information:
Number of banks | item	4
Property and equipment	$ 98,390	$ 56,557
Geographic Concentration Risk | Outside United States
Segment information:
Property and equipment	$ 699	$ 287
Revenue | Geographic Concentration Risk | Outside United States
Segment information:
Risk percentage	7.00%	5.00%	4.00%
Revenue | No customer concentration >10% | Outside United States
Segment information:
Risk percentage	0.00%	0.00%	0.00%

SUMMARY OF SIGNIFICANT ACCOUN_7

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Registration (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	Jul. 31, 2020	Jul. 28, 2020	Apr. 03, 2020	Dec. 31, 2020	Dec. 31, 2019
Initial Public Offering
Forward Stock Split		three-for-one
Stock split		0.33
Proceeds from issuance of shares in connection with Offering				$ 423,024
Principal payments on long-term debt				$ 226,251	$ 5,566
Term Loan
Initial Public Offering
Principal payments on long-term debt	$ 175,000		$ 61,656
Initial Public Offering | Class A
Initial Public Offering
Proceeds from issuance of shares in connection with Offering	$ 423,024
Stock issued during the period		23,812
Price (per share)		$ 19

SUMMARY OF SIGNIFICANT ACCOUN_8

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Useful life (Details)	12 Months Ended
	Dec. 31, 2021
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) - ESPP - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Compensation plans:
Discount	15.00%
Reserved for issuance		1,000,000
Shares available for issuance	2,278
Maximum issuance (as a percentage of outstanding)	1.00%
Maximum issuance (in shares)	16,000,000

SUMMARY OF SIGNIFICANT ACCOU_10

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revenue Recognition (Details)	12 Months Ended
	Dec. 31, 2021
Deferred revenue recognition:
Payment terms (in days)	30 days
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-09-30
Deferred revenue recognition:
Revenue recognition period	3 years

SUMMARY OF SIGNIFICANT ACCOU_11

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Foreign Currency (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Other operating expense (income), net
Foreign currency
Net foreign transaction gains (losses)	$ 183	$ (155)	$ (84)

SUMMARY OF SIGNIFICANT ACCOU_12

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Supplemental Balance Sheet Information (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Prepaid expenses and other current assets:
Prepaid expenses	$ 12,251	$ 6,334
Prepaid licenses and support	8,285	6,925
Prepaid expenses and other current assets	20,536	13,259
Accrued expenses:
Accrued general expenses	17,894	15,964
Accrued professional fees	2,565	631
Accrued income and other taxes	2,507	2,581
Accrued expenses	$ 22,966	$ 19,176

SUMMARY OF SIGNIFICANT ACCOU_13

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Supplemental Cash Flow Disclosures (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Cash paid for Interest	$ 223	$ 2,461	$ 1,766
Cash paid for income taxes, net of refunds	1,287	588	945
Operating cash flows from operating leases	4,692
Non-cash investing and financing activities:
Distributions payable			13,183
Estimated distributions payable under Tax Sharing Agreement	536	2,700
Purchase commitment and contingent consideration liabilities	12,736	12,592
Contingent consideration liability	39,024
Remeasurement of options for redeemable shares		51,833	2,763
Conversion of SAR's in connection with the Offering		129,710
Exchange of Amended Options in connection with the Offering		69,177
Exercised options exchanged in lieu of income taxes			184
Leased assets obtained in exchange for new finance lease liabilities	$ 173
Equipment acquired through capital leases		$ 646	$ 1,904

SUMMARY OF SIGNIFICANT ACCOU_14

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Recently Issued Accounting Pronouncements (Details) - USD ($) $ in Thousands	Jan. 01, 2021	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020
Recently issued accounting pronouncements
Lease, Practical Expedients, Package [true false]		true
Operating lease right-of-use assets		$ 20,249
Operating lease liabilities		28,253
Retained earnings		$ 24,811	$ 25,438	$ 29,386	$ 28,578	$ 25,782	$ 25,552
ASU 2016-02
Recently issued accounting pronouncements
Operating lease right-of-use assets	$ 24,004
Operating lease liabilities	32,562
Deferred rent written off	9,554
Retained earnings	$ 508

REVENUE RECOGNITION - Disaggreg

REVENUE RECOGNITION - Disaggregation of revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of revenue:
Revenues	$ 425,548	$ 374,665	$ 321,500
Software subscriptions
Disaggregation of revenue:
Revenues	358,415	316,763	275,629
Software licenses
Disaggregation of revenue:
Revenues	231,371	229,744	223,116
Cloud subscriptions
Disaggregation of revenue:
Revenues	127,044	87,019	52,513
Services
Disaggregation of revenue:
Revenues	$ 67,133	$ 57,902	$ 45,871

REVENUE RECOGNITION - Accounts

REVENUE RECOGNITION - Accounts receivable, net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
REVENUE RECOGNITION
Allowance for accounts receivable	$ 9,151	$ 8,592	$ 7,515	$ 5,527
Allowance for credit loss
Balance, beginning of period	77,159	70,367
Balance, end of period	76,929	77,159
(Decrease) increase, net	$ (230)	$ 6,792

REVENUE RECOGNITION - Allowance

REVENUE RECOGNITION - Allowance and deferred allowance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Allowance for credit loss
Beginning balance	$ (8,592)	$ (7,515)	$ (5,527)
Ending balance	(9,151)	(8,592)	(7,515)
Change in allowance	559	1,077	1,988
Deferred beginning balance	6,432	5,614	4,858
Deferred ending balance	6,537	6,432	5,614
Change in deferred allowance	(105)	(818)	(756)
Net amount charged to revenues	454	259	1,232
Revenue recognized for satisfaction	$ 207,560	$ 191,745	$ 163,939

REVENUE RECOGNITION - Deferred

REVENUE RECOGNITION - Deferred revenue (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
REVENUE RECOGNITION
Deferred revenue, current	$ 237,344	$ 207,560
Deferred revenue, non-current	11,666	14,702
Total deferred revenue	$ 249,010	$ 222,262	$ 205,791	$ 178,703

REVENUE RECOGNITION - Changes t

REVENUE RECOGNITION - Changes to deferred revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
REVENUE RECOGNITION
Beginning balance	$ 222,262	$ 205,791	$ 178,703
Additional amounts deferred	452,296	391,136	348,588
Revenues recognized	(425,548)	(374,665)	(321,500)
Ending balance	$ 249,010	$ 222,262	$ 205,791

REVENUE RECOGNITION - Deferre_2

REVENUE RECOGNITION - Deferred revenue, recognized (Details) $ in Thousands	Dec. 31, 2021USD ($)
REVENUE RECOGNITION
2022	$ 237,344
2023	10,161
2024	1,505
Total	$ 249,010

REVENUE RECOGNITION - Contract

REVENUE RECOGNITION - Contract cost balances (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Changes to deferred commissions:
Beginning balance	$ 11,743	$ 11,196	$ 8,830
Additions	10,018	8,291	10,140
Amortization	(9,206)	(7,744)	(7,774)
Ending balance	$ 12,555	11,743	11,196
Contract costs, amortization period	3 years
Impairment loss	$ 0	$ 0	$ 0

BUSINESS COMBINATIONS (Details)

BUSINESS COMBINATIONS (Details) $ in Thousands	Sep. 22, 2021USD ($)	May 12, 2021USD ($)	Jan. 25, 2021USD ($)payment	Jan. 07, 2020USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2020USD ($)	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Sep. 30, 2021USD ($)	Aug. 19, 2021USD ($)
Business combinations
Cash consideration, net							$ 251,412	$ 11,570
Deferred purchase consideration, current							19,805
Deferred purchase consideration, net of current portion							19,419
Payments for purchase commitment liability							10,822
Revenues							425,548	374,665	$ 321,500
Net income (loss)					$ (17,172)	$ (75,311)	$ (1,479)	(75,081)	$ 31,057
Systax - VIE
Business combinations
Ownership (as a percent)							65.00%
General and administrative
Business combinations
Transaction costs								504
LCR-Dixon
Business combinations
Cash consideration	$ 59,720
Purchase price	98,744
Royalties payable written off	252
Cash received in the acquisition	1,899
Cash consideration, net	57,821
Aggregate deferred payments	40,000
Amount per installment of deferred payment	10,000
Fair value of deferred payment, net of discount	39,024
Amount of discount of deferred payments	$ 976
Deferred purchase consideration, current										$ 19,805
Deferred purchase consideration, net of current portion										$ 19,419
Taxamo
Business combinations
Cash consideration		$ 190,153
Fair value of acquisition holdbacks		502
Fair value of purchase commitment liability		10,034									$ 10,034
Purchase price		200,689
Cash received in the acquisition		2,662
Restricted cash acquired from acquisition		221
Cash consideration, net		187,491
Holdback		$ 502					$ 468
Percentage of remaining outstanding share of the acquiree											5.00%
Interest acquired (as a percent)		95.00%									100.00%
Additional equity interests acquired		5.00%
Payments for purchase commitment liability		$ 10,034
Taxamo | Other operating expense (income), net
Business combinations
Transaction costs							4,269
Tellutax
Business combinations
Cash consideration			$ 6,100
Contingent consideration			$ 2,200
Number of potential earnout payments | payment			3
Revenue achievement period			30 months
Maximum limit on earnout payments			$ 0
Earn out payment for applicable measurement period			$ 0
Tellutax | Estimated linear obsolescence factor
Business combinations
Value of input used to measure capitalized software			20
Tellutax | Revenue discount rate
Business combinations
Value of input used to measure capitalized software			28.5
Systax
Business combinations
Cash held in escrow for benefit of Systax Quataholders				$ 748
Cash consideration				12,374
Fair value of purchase commitment liability							788
Purchase commitment liability				12,592				845
Purchase price				24,966
Holdback				$ 14
Adjustment due to currency exchange rates fluctuation							$ 0
Interest acquired (as a percent)				60.00%			65.00%
Additional equity interests acquired							5.00%
Payments for purchase commitment liability							$ 8,329	$ 8,905
Systax | Quotaholders
Business combinations
Cash consideration				$ 11,626
Percentage of remaining outstanding share of the acquiree				40.00%

BUSINESS COMBINATIONS - Net ass

BUSINESS COMBINATIONS - Net assets and liabilities (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)segment	Sep. 22, 2021USD ($)	May 12, 2021USD ($)	Jan. 25, 2021USD ($)	Dec. 31, 2020USD ($)	Jan. 07, 2020USD ($)	Dec. 31, 2019USD ($)
Business combinations
Operating segments | segment	1
Goodwill	$ 270,041				$ 16,329		$ 0
LCR-Dixon
Business combinations
Cash and cash equivalents		$ 1,899
Accounts receivable		1,437
Prepaid expenses and other current assets		326
Property and equipment		4
Goodwill		96,968
Accounts payable		(19)
Accrued expenses		(306)
Accrued compensation		(1,746)
Deferred revenue		(71)
Total		$ 98,492
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		502
Goodwill			164,199
Other intangible assets			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 - Developed technology				$ 3,600
Goodwill				4,700
Total				$ 8,300
Systax
Business combinations
Cash and cash equivalents						$ 56
Accounts receivable						495
Property and equipment						112
Holdback						14
Goodwill						21,089
Other intangible assets						3,650
Accounts payable						(358)
Accrued expenses						(92)
Total						$ 24,966

BUSINESS COMBINATIONS - Assumpt

BUSINESS COMBINATIONS - Assumptions of intangible assets acquired in the acquisition (Details) - USD ($) $ in Thousands	May 12, 2021	Dec. 31, 2021
Developed Technology
Business combinations
Fair Value		$ 40,746
Taxamo | Developed Technology | Property and Equipment, net
Business combinations
Fair Value	$ 40,746
Estimated Useful Life	3 years
Discount Rate	16.50%
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%

FINANCIAL INSTRUMENTS AND FAI_3

FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS (Details) $ in Thousands	Jan. 25, 2021USD ($)payment	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)
Fair Value, Recurring
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Money market funds		$ 10,703	$ 265,270
Prices in active markets for identical assets (Level 1)
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Money market funds		10,703	$ 265,270
Significant other observable inputs (Level 2)
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Forward foreign current contract, asset		448
Forward foreign currency contract, liability		(62)
Tellutax
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Tellutax contingent consideration	$ 2,200	2,500
Number of potential earnout payments | payment	3
Revenue achievement period	30 months
Maximum limit on earnout payments	$ 0
Earn out payment for applicable measurement period	$ 0
Tellutax | Fair Value, Recurring
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Tellutax contingent consideration		2,500
Tellutax | Significant unobservable inputs (Level 3)
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Tellutax contingent consideration		$ 2,500

FINANCIAL INSTRUMENTS AND FAI_4

FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS - Estimated fair values of Tellutax contingent consideration (Details) - Tellutax $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)Y	Jan. 25, 2021USD ($)Y
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Tellutax contingent consideration	$ (2,500)	$ (2,200)
Fair value adjustments to contingent consideration	$ 300
Revenue volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration measurement input	95	95
Revenue discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration measurement input	20	20.3
Term (in years)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration measurement input | Y	3.6	4.3

FINANCIAL INSTRUMENTS AND FAI_5

FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS - Changes in fair value of Tellutax contingent consideration (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)
Contingent Consideration
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Acquisition of Tellutax	$ (2,200)
Fair value adjustments	(300)
Balance, December 31, 2021	(2,500)
LCR-Dixon
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Deferred purchase consideration	39,224
Systax
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Purchase commitment liability	$ 8,329

PROPERTY AND EQUIPMENT (Details

PROPERTY AND EQUIPMENT (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property and equipment
Property and equipment, gross	$ 246,605	$ 175,687
Less accumulated depreciation	(148,215)	(119,130)
Property and equipment, net	98,390	56,557
Leasehold improvements
Property and equipment
Property and equipment, gross	20,956	20,907
Equipment
Property and equipment
Property and equipment, gross	41,937	41,410
Computer software purchased
Property and equipment
Property and equipment, gross	11,792	11,620
Internal-Use Software
Property and equipment
Property and equipment, gross	147,280	90,772
Less accumulated depreciation	(87,281)	(65,090)
Property and equipment, net	76,964	28,986
Cloud-based customer solutions
Property and equipment
Property and equipment, gross	114,872	65,423
Internal systems and tools
Property and equipment
Property and equipment, gross	32,408	25,349
Furniture and fixtures
Property and equipment
Property and equipment, gross	7,675	7,674
In-process internal-use software
Property and equipment
Property and equipment, gross	$ 16,965	$ 3,304

PROPERTY AND EQUIPMENT - Additi

PROPERTY AND EQUIPMENT - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Property and equipment
Finance lease amortization	$ 931
Property and equipment	98,390	$ 56,557
Accumulated depreciation	148,215	119,130
Developed Technology
Property and equipment
Depreciation expense	8,123
Fair Value	40,746
Excluding internal-use software and capital leases
Property and equipment
Depreciation expense	7,425	7,833	$ 7,386
Assets under finance leases
Property and equipment
Property and equipment	1,533
Accumulated depreciation	931
Assets under capital leases
Property and equipment
Property and equipment		1,360	1,455
Accumulated depreciation		1,370	627
Depreciation expense		743	565
Internal-Use Software
Property and equipment
Property and equipment	76,964	28,986
Accumulated depreciation	87,281	65,090
Depreciation expense	19,076	8,818	7,982
Internal systems and tools
Property and equipment
Depreciation expense	$ 3,322	$ 2,442	$ 1,045

PROPERTY AND EQUIPMENT - Major

PROPERTY AND EQUIPMENT - Major components of internal-use software (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property and equipment
Property and equipment, gross	$ 246,605	$ 175,687
Less accumulated depreciation	(148,215)	(119,130)
Property and equipment	98,390	56,557
Internal-Use Software
Property and equipment
Property and equipment, gross	147,280	90,772
Less accumulated depreciation	(87,281)	(65,090)
Property and equipment, net excluding in-process internal-use software	59,999	25,682
Property and equipment	76,964	28,986
In-process internal-use software
Property and equipment
Property and equipment, gross	$ 16,965	$ 3,304

PROPERTY AND EQUIPMENT - Amount

PROPERTY AND EQUIPMENT - Amounts capitalized for internal-use software and included in property and equipment additions on the consolidated statements of cash flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Property and equipment
Capitalized internal-use software	$ 33,386	$ 20,955	$ 20,339
Internal-Use Software
Property and equipment
Capitalized internal-use software	31,328	17,886	15,039
Cloud-based customer solutions
Property and equipment
Capitalized internal-use software	19,837	14,710	10,179
Internal systems and tools
Property and equipment
Capitalized internal-use software	$ 11,491	$ 3,176	$ 4,860

PROPERTY AND EQUIPMENT - Amorti

PROPERTY AND EQUIPMENT - Amortization expense (Details) $ in Thousands	Dec. 31, 2021USD ($)
Internal systems and tools
Software
2022	$ 3,861
2023	2,831
2024	1,988
2025	845
2026	122
Total	9,647
Cloud-based customer solutions
Software
2022	24,740
2023	19,624
2024	5,988
Total	$ 50,352

CAPITALIZED SOFTWARE (Details)

CAPITALIZED SOFTWARE (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Capitalized software, bgn
Capitalized software, net	$ 33,442	$ 31,989
Capitalized software additions	3,600
Capitalized software amortization expense	12,962	11,936	$ 8,212
Software
Capitalized software, bgn
Capitalized software, gross	72,512	63,071
Less accumulated amortization	(45,179)	(32,217)
Capitalized software, net	27,333	30,854
Capitalized development costs	11,660	11,850	$ 17,221
In-process internal-use software
Capitalized software, bgn
Capitalized software, gross	$ 6,109	$ 1,135

CAPITALIZED SOFTWARE - Amortiza

CAPITALIZED SOFTWARE - Amortization expense (Details) - Software $ in Thousands	Dec. 31, 2021USD ($)
Future amortization expense:
2022	$ 11,352
2023	8,514
2024	5,802
2025	1,416
2026	249
Total	$ 27,333

LEASES (Details)

LEASES (Details)	12 Months Ended
	Dec. 31, 2021
Maximum
Remaining lease term (in years)	7 years

LEASES - Lease Assets and Liabi

LEASES - Lease Assets and Liabilities (Details) $ in Thousands	Dec. 31, 2021USD ($)
Lease assets:
Operating lease right-of-use assets	$ 20,249
Finance lease assets	$ 602
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Property, Plant and Equipment, Net
Total lease assets	$ 20,851
Current:
Operating lease liabilities	3,933
Finance lease liabilities	284
Total current lease liabilities	4,217
Non-current:
Operating lease liabilities, non-current	24,320
Finance lease liabilities, non-current	68
Total non-current lease liabilities	24,388
Total lease liabilities	$ 28,605

LEASES - Lease Costs, Weighted

LEASES - Lease Costs, Weighted Average Term and Rates (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)
Lease Cost, Weighted average term and discount rate:
Operating lease cost	$ 4,774
Amortization of lease assets	931
Interest on lease liabilities	16
Total lease cost	$ 5,721
Operating leases, weighted-average remaining lease term (in years)	6 years 7 months 6 days
Finance leases, weighted-average remaining lease term (in years)	1 year 2 months 12 days
Operating leases, weighted-average discount rate	2.30%
Finance leases, weighted-average discount rate	2.30%

LEASES - Future Maturity of Lea

LEASES - Future Maturity of Lease Liabilities (Details) $ in Thousands	Dec. 31, 2021USD ($)
Operating Leases
2022	$ 4,593
2023	4,459
2024	4,464
2025	4,382
2026	4,477
Thereafter	8,054
Total lease payments	30,429
Less: Imputed Interest	(2,176)
Present value of lease liabilities	28,253
Finance Leases
2022	289
2023	59
2024	10
Total lease payments	358
Less: Imputed Interest	(6)
Present value of lease liabilities	$ 352

LEASES - Future Maturity of L_2

LEASES - Future Maturity of Lease Liabilities under ASU 840 (Details) $ in Thousands	Dec. 31, 2020USD ($)
Operating Leases
2021	$ 5,442
2022	4,518
2023	4,459
2024	4,464
2025	4,382
Thereafter	12,531
Total Lease Payments	35,796
Finance Leases
2021	915
2022	230
Total Lease Payments	1,145
Less amount representing interest	(38)
Present value of minimum lease payments	1,107
Less current portion	(882)
Capital lease obligations, net of current portion	$ 225

GOODWILL AND OTHER INTANGIBLE_3

GOODWILL AND OTHER INTANGIBLE ASSETS (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Goodwill.	$ 270,041	$ 16,329	$ 0
Goodwill and other intangible assets	272,702	18,711
Other intangible assets
Finite-Lived Intangible Assets [Line Items]
Other intangible assets, net	$ 2,661	$ 2,382

GOODWILL AND OTHER INTANGIBLE_4

GOODWILL AND OTHER INTANGIBLE ASSETS - Changes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Balance, January 1, 2021	$ 16,329	$ 0
Acquisition	265,867	21,089
Foreign currency translation adjustments	(12,155)	(4,760)
Balance, September 30, 2021, gross	270,041	16,329
Accumulated impairment losses		0
Balance, September 30, 2021, net	$ 270,041	$ 16,329

GOODWILL AND OTHER INTANGIBLE_5

GOODWILL AND OTHER INTANGIBLE ASSETS - Intangibles (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Amortization of acquired intangible assets
Amortization	$ 1,066	$ 443
Cost of Revenues
Amortization of acquired intangible assets
Amortization	253	267
Selling and marketing
Amortization of acquired intangible assets
Amortization	$ 813	$ 176
Other intangible assets
Other intangible assets
Weighted Average Amortization Period (Years)	4 years 2 months 12 days	5 years 6 months
Gross Value	$ 4,110	$ 2,825
Accumulated Amortization	(1,449)	(443)
Carrying Value	$ 2,661	$ 2,382

GOODWILL AND OTHER INTANGIBLE_6

GOODWILL AND OTHER INTANGIBLE ASSETS - Future amortization (Details) - Other intangible assets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Future amortization expense:
2022	$ 1,203
2023	743
2024	466
2025	249
Total	$ 2,661	$ 2,382

DEBT - Credit Agreement (Detail

DEBT - Credit Agreement (Details) - USD ($) $ in Thousands	Jul. 31, 2020	May 29, 2020	Apr. 03, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Debt
Refund on payments for deferred financing costs					$ 468
Principal payments on long-term debt					226,251	$ 5,566
Distribution paid		$ 123,185			146,116	$ 28,566
Base rate
Debt
Interest rate				3.25%
LIBOR
Debt
Interest rate				2.00%
Term Loan
Debt
Face amount			$ 175,000
Payments for deferred financing costs			2,904
Write off deferred financing costs					1,174
Principal payments on long-term debt	$ 175,000		61,656
Line of Credit
Debt
Line of credit, capacity			$ 100,000
Line of credit, outstanding borrowings				$ 0	$ 0
Maturity date				Mar. 1, 2025

STOCKHOLDERS EQUITY (Details)

STOCKHOLDERS EQUITY (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands

Jun. 30, 2021

Jul. 31, 2020

Jul. 28, 2020

Jul. 25, 2020

Jun. 30, 2020

Apr. 30, 2020

Mar. 31, 2020

Dec. 31, 2021

Dec. 31, 2020

Dec. 31, 2019

Mar. 15, 2022

Jul. 27, 2020

Common Stock

Additional paid in capital

$ 222,621

$ 206,541

Forward Stock Split

three-for-one

Stock split

0.33

Liquidation preferences

$ 0

$ 0

Common stock, shares authorized (in shares)

450,000

Common stock par value (per share)

$ 0.001

Preferred stock, shares authorized (in shares)

30,000

30,000

30,000

Preferred stock par value (per share)

$ 0.001

$ 0.001

$ 0.001

Proceeds from issuance of shares in connection with Offering

$ 423,024

Proceeds from exercise of stock option

$ 1,859

8,808

$ 68

Distributions

$ 5,706

$ 123,185

$ 4,010

$ 132,901

$ 30,857

Distributions per share

$ 0.05

$ 1.02

$ 0.03

Period with in the company is required settle any remaining liability for taxes to the former S-corporation shareholders

15 days

Exchange of shares

300

Repurchased Treasury Stock

Common Stock

Treasury stock acquired

41,910

Family

Common Stock

Ownership (as a percent)

99.90%

ESPP

Common Stock

Auto exercised options in connection with offering shares issued

128

Former Class A

Common Stock

Common Stock, Shares, Outstanding

147

Former Class A | Family

Common Stock

Ownership (as a percent)

100.00%

Former Class B

Common Stock

Common Stock, Shares, Outstanding

120,443

Proceeds from exercise of stock option

$ 53

Stock issued during the period

173

Former Class B | Family

Common Stock

Common Stock, Shares, Outstanding

120,270

Former Class B | Selling stockholders

Common Stock

Common Stock, Shares, Outstanding

173

Class A

Common Stock

Common Stock, Shares, Outstanding

42,286

26,327

Common stock, shares authorized (in shares)

300,000

300,000

300,000

Common stock par value (per share)

$ 0.001

$ 0.001

Common Stock, Voting Rights

one

Shares exchanged in lieu

381

860

Class A | Exercise of outstanding options

Common Stock

Exercise of stock options, net (in shares)

890

New Issues Vested Restricted Stock, Shares

19

Class A | In connection with the offering

Common Stock

Auto exercised options in connection with offering shares issued

564

Class A | Initial Public Offering

Common Stock

Offering costs

$ 6,222

Proceeds from issuance of shares in connection with Offering

$ 423,024

Stock issued during the period

23,812

Class A | Selling stockholders

Common Stock

Auto exercised options in connection with offering shares issued

2,157

Shares exchanged in lieu

706

Stock issued during the period

510

Class A | Restricted Stock Units

Common Stock

Shares issued upon vesting of RSU's, net (in shares)

12

Class A | Restricted Stock Awards

Common Stock

Shares issued upon vesting of RSU's, net (in shares)

352

Class A | Restricted Stock Awards | Exercise of outstanding options

Common Stock

Exercise of stock options, net (in shares)

890

New Issues Vested Restricted Stock, Shares

19

Class A | ESPP

Common Stock

Stock issued during the period

59

Class B

Common Stock

Common Stock, Shares, Outstanding

106,807

120,117

Common stock, shares authorized (in shares)

150,000

150,000

150,000

Common stock par value (per share)

$ 0.001

$ 0.001

Common Stock, Voting Rights

ten

Exchange of shares

13,310

Common Stock

Common Stock

Common Stock, Shares, Outstanding

120,590

Share exchange, amount

$ 0

S Corporation

Common Stock

Additional paid in capital

$ 354,291

Amount of estimated dividends liability

$ 2,733

$ 536

EARNINGS PER SHARE (Details)

EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Numerator:
Net (loss) income attributable to all stockholders	$ (17,172)	$ (75,311)	$ (1,479)	$ (75,081)	$ 31,057
Class A
Numerator:
Common stock as a percentage of total shares outstanding, basic			24.12%	8.44%	0.08%
Net income (loss) attributable to stockholders, basic	(2,246)	(2,278)	$ (357)	$ (6,335)	$ 23
Common stock as a percentage of total shares outstanding, diluted			24.12%	8.44%	3.11%
Net income (loss) attributable to stockholders, diluted	$ (2,246)	$ (2,278)	$ (357)	$ (6,335)	$ 965
Denominator:
Weighted average common stock, basic (in shares)			35,647,000	11,096,000	118,000
Dilutive effect of common stock equivalents					3,743,000
Weighted average common stock, diluted (in shares)			35,647,000	11,096,000	3,861,000
Net income (loss) per share, basic (in dollars per share)	$ (0.12)	$ (0.37)	$ (0.01)	$ (0.57)	$ 0.20
Net income (loss) per share, diluted (in dollars per share)	$ (0.12)	$ (0.37)	$ (0.01)	$ (0.57)	$ 0.25
Class A | Amended Options
Denominator:
Anti-dilutive shares			10,422	7,398
Class A | Out-of-the-money options
Denominator:
Anti-dilutive shares			294
Class A | Restricted Stock Awards
Denominator:
Anti-dilutive shares			490	289
Class A | Restricted Stock Units
Denominator:
Anti-dilutive shares			387	27
Class A | ESPP
Denominator:
Anti-dilutive shares			29
Class B
Numerator:
Common stock as a percentage of total shares outstanding, basic			75.88%	91.56%	99.92%
Net income (loss) attributable to stockholders, basic	$ (14,926)	$ (73,033)	$ (1,122)	$ (68,746)	$ 31,034
Common stock as a percentage of total shares outstanding, diluted			75.88%	91.56%	96.89%
Net income (loss) attributable to stockholders, diluted	$ (14,926)	$ (73,033)	$ (1,122)	$ (68,746)	$ 30,092
Denominator:
Weighted average common stock, basic (in shares)			112,133,000	120,415,000	120,417,000
Weighted average common stock, diluted (in shares)			112,133,000	120,415,000	120,417,000
Net income (loss) per share, basic (in dollars per share)	$ (0.12)	$ (0.61)	$ (0.01)	$ (0.57)	$ 0.26
Net income (loss) per share, diluted (in dollars per share)	$ (0.12)	$ (0.61)	$ (0.01)	$ (0.57)	$ 0.25

EMPLOYEE BENEFIT AND DEFERRED_3

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - 401K Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Compensation plans:
Contribution (as a percent)	3.00%	3.00%	3.00%
401(k) matching contributions	$ 4,062	$ 4,011	$ 3,419
Discretionary profit-sharing
Compensation plans:
Contribution (as a percent)	3.00%	3.00%	3.00%
401(k) discretionary contributions	$ 3,994	$ 4,035	$ 3,363

EMPLOYEE BENEFIT AND DEFERRED_4

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - Long-Term Rewards Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2023	Dec. 31, 2022
Compensation plans:
Performance period (in years)	three-year
Deferred compensation, current	$ 4,202	$ 2,057
Deferred compensation, net of current portion	1,963	5,010
Long-Term Rewards Plan
Compensation plans:
Compensation expense	3,059	3,027	$ 2,462
Deferred compensation, current	$ 1,981	$ 2,796
Long-Term Rewards Plan | Forecast
Compensation plans:
Deferred compensation, net of current portion				$ 1,778	$ 4,060

EMPLOYEE BENEFIT AND DEFERRED_5

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - Stock-Based Award Plans (Details) - USD ($) shares in Thousands, $ in Thousands	Jul. 28, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Compensation plans:
Accrued salaries and benefits		$ 16,671	$ 17,326
ESPP
Compensation plans:
Offering Period		6 months
Accrued salaries and benefits		$ 281	$ 246
SAR
Compensation plans:
Shares converted	12,038
Outstanding vested and expected to vest (in shares)				12,276	10,671
Amended Options
Compensation plans:
Shares converted	3,676

EMPLOYEE BENEFIT AND DEFERRED_6

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - 2020 Plan (Details) - 2020 Plan shares in Thousands	12 Months Ended
	Dec. 31, 2021shares
Compensation plans:
Shares authorized	16,500
Available for issuance	6,490
Maximum issuance (as a percentage of outstanding)	4.00%
Maximum issuance (in shares)	3,000

EMPLOYEE BENEFIT AND DEFERRED_7

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - Retired SAR Plan (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	Jul. 28, 2020	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Compensation plans:
Redemption of Converted SARs							$ (22,889)
Deferred compensation, current		$ 4,202				$ 4,202	2,057
Deferred compensation, net of current portion		$ 1,963				1,963	5,010
Stock-based compensation expense						25,458	12,576
Stock-based compensation expense						$ 26,160	147,904	$ 9,460
Fair Value Assumptions and Methodology
Share Price	$ 19
Volatility	36.70%	37.10%	37.10%	36.80%	36.80%	37.40%
Expected term (in years)	6 years 6 months	5 years	5 years	6 years	6 years	5 years
Risk-free interest rate	0.40%	0.90%	0.80%	0.40%	0.40%	1.30%
SAR
Compensation plans:
Outstanding (in shares)								6,207	5,889
Percentage of vesting to exercise								50.00%
Outstanding vested and expected to vest (in shares)								12,276	10,671
Exercised options exchanged in lieu of income taxes	$ 13,835
Aggregate intrinsic value	9,054
Unrecognized compensation expense		$ 44,342				$ 44,342	44,342
Deferred compensation, current	1,299						1,299
Deferred compensation, net of current portion		$ 1,122				1,122	1,122
Stock-based compensation expense	57,079					$ 143,519
Fair value, vested and expected to vest	$ 197,708
Fair value of options							153,366
Incremental compensation expense							$ 0
Fair Value Assumptions and Methodology
Share Price	$ 19
SAR | Minimum
Compensation plans:
Service requirement (in years)						1 year	1 year
Unrecognized compensation expense period	1 year
SAR | Maximum
Compensation plans:
Service requirement (in years)						10 years	5 years
Unrecognized compensation expense period	5 years
SAR | Accounting Standards Update 2016-09
Compensation plans:
Unrecognized compensation expense							$ 2,422

EMPLOYEE BENEFIT AND DEFERRED_8

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - SAR Plan, activity (Details) - $ / shares shares in Thousands	Jul. 01, 2020	Dec. 31, 2020	Dec. 31, 2019
Grant values
Granted		$ 4.70
Forfeited		2.50
Grant values, Nonvested
Forfeited		$ 2.50
Weighted average grant date intrinsic value	$ 0
SAR
Vested and Expected to Vest
Balance, Bgn		12,276	10,671
Granted		702	2,409
Exercised		(877)	(609)
Forfeited		(63)	(195)
Converted		(12,038)
Balance, End			12,276
Vested
Balance, Bgn		6,207	5,889
Exercised		(877)	(609)
Vested		1,410	630
Balance, End			6,207
Nonvested Units
Balance, Bgn		6,069	4,782
Forfeited		(63)	(195)
Vested		(1,410)	(630)
Balance, End			6,069
Grant values
Granted			$ 3.73
SAR | Minimum
Grant values
Balance, Bgn		$ 0.92	0.92
Vested			0.92
Exercised		1.31	1.31
Forfeited			2.13
Converted		0.92
Balance, End			0.92
Grant values, Vested
Exercised		1.31	1.31
Grant values, Nonvested
Forfeited			2.13
SAR | Maximum
Grant values
Balance, Bgn		3.73	3.17
Vested			3.73
Exercised		2.50	2.50
Forfeited			2.50
Converted		4.70
Balance, End			3.73
Grant values, Vested
Exercised		$ 2.50	2.50
Grant values, Nonvested
Forfeited			$ 2.50
Vested units
Vested and Expected to Vest
Granted		21	297
Converted		(6,761)
Non vested units
Vested and Expected to Vest
Granted		681	2,112
Converted		(5,277)

EMPLOYEE BENEFIT AND DEFERRED_9

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - Amended Options (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Compensation plans:
Remeasurement of options for redeemable shares			$ 51,833	$ 2,763
Amended Options
Compensation plans:
Triggering event (as percentage of stock)		50.00%
Partial triggering event		25.00%
Tag along right		51.00%
Drag along right		51.00%
Remeasurement of options for redeemable shares		$ 51,833	$ 2,763
Temporary equity and were reclassified to stockholders' equity		$ 69,177
Units
Balance, Bgn	4,125	3,849	4,125
Exercised	(173)		(276)
Exchange		(3,676)
Balance, End			3,849	4,125
Weighted Average Per Share
Balance, Bgn	$ 0.19		$ 0.19	$ 0.20
Exercised			0.30	0.25
Exchange			$ 0.19
Balance, End				$ 0.19
Aggregate intrinsic value
Beginning of period	$ 17,344		$ 17,344	$ 14,581
Exercised			759	957
Amendment and exchange of options			$ 69,177
End of period				$ 17,344

EMPLOYEE BENEFIT AND DEFERRE_10

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - Options under 2020 Plan (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	Jul. 28, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Weighted Average Per Share
Compensation expense		$ 26,160	$ 147,904	$ 9,460
2020 Plan
Units
Balance, Bgn		11,876
Granted		779	15,714
Forfeited		(292)	(156)
Exercised		(2,863)	(3,682)
Balance, End		9,500	11,876
Exercisable		6,169
Weighted Average Per Share
Balance, Bgn		$ 2.44
Granted		23.06	$ 2.16
Forfeited		4.06	3.29
Exercised		2.04	1.21
Balance, End		4.20	$ 2.44
Exercisable		$ 2.39
Remaining contractual life, outstanding		5 years 2 months 12 days	5 years 3 months 18 days
Remaining contractual life, exercisable		3 years 10 months 24 days
Intrinsic value, outstanding		$ 110,843	$ 384,883
Intrinsic value, exercisable		$ 83,188
Vesting period		10 years
Unrecognized compensation expense		$ 18,742
Unrecognized compensation expense period		2 years 9 months 18 days
2020 Plan | Minimum
Weighted Average Per Share
Vesting period		1 year
2020 Plan | Maximum
Weighted Average Per Share
Vesting period		4 years
Unrecognized compensation expense period	5 years
Converted Options
Units
Granted			12,038
Weighted Average Per Share
Granted			$ 2.76
Amended Options.
Units
Granted			3,676
Weighted Average Per Share
Granted			$ 0.19

EMPLOYEE BENEFIT AND DEFERRE_11

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - Options under 2020 Plan Price Range (Details) shares in Thousands	12 Months Ended
	Dec. 31, 2021$ / sharesshares
Options outstanding, vested and exercisable:
Options outstanding	9,500
Options vested and exercisable	6,169
$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	1,854
$2.15
Options outstanding, vested and exercisable:
Exercise prices | $ / shares	$ 2.15
Options outstanding	462
Options outstanding, life	3 years 1 month 6 days
Options vested and exercisable	462
Options vested and exercisable, life	3 years 1 month 6 days
$2.50
Options outstanding, vested and exercisable:
Exercise prices | $ / shares	$ 2.50
Options outstanding	2,186
Options outstanding, life	4 years 6 months
Options vested and exercisable	2,186
Options vested and exercisable, life	4 years 6 months
$2.67
Options outstanding, vested and exercisable:
Exercise prices | $ / shares	$ 2.67
Options outstanding	419
Options outstanding, life	5 years 2 months 12 days
Options vested and exercisable	42
Options vested and exercisable, life	5 years 1 month 6 days
$3.17
Options outstanding, vested and exercisable:
Exercise prices | $ / shares	$ 3.17
Options outstanding	1,196
Options outstanding, life	6 years 3 months 18 days
Options vested and exercisable	446
Options vested and exercisable, life	6 years 3 months 18 days
$3.73
Options outstanding, vested and exercisable:
Exercise prices | $ / shares	$ 3.73
Options outstanding	1,932
Options outstanding, life	7 years 9 months 18 days
Options vested and exercisable	1,061
Options vested and exercisable, life	7 years 9 months 18 days
$4.70
Options outstanding, vested and exercisable:
Exercise prices | $ / shares	$ 4.70
Options outstanding	683
Options outstanding, life	8 years 1 month 6 days
$18.47
Options outstanding, vested and exercisable:
Exercise prices | $ / shares	$ 18.47
Options outstanding	213
Options outstanding, life	9 years 10 months 24 days
$18.96
Options outstanding, vested and exercisable:
Exercise prices | $ / shares	$ 18.96
Options outstanding	235
Options outstanding, life	9 years 7 months 6 days
Options vested and exercisable	105
Options vested and exercisable, life	9 years 7 months 6 days
$19.00
Options outstanding, vested and exercisable:
Exercise prices | $ / shares	$ 19
Options outstanding	69
Options outstanding, life	9 years 8 months 12 days
$32.16
Options outstanding, vested and exercisable:
Exercise prices | $ / shares	$ 32.16
Options outstanding	251
Options outstanding, life	9 years 2 months 12 days
Options vested and exercisable	13
Options vested and exercisable, life	9 years 2 months 12 days

EMPLOYEE BENEFIT AND DEFERRE_12

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - Options under 2020 Plan Options issued (Details) - $ / shares	Jul. 28, 2020	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2021
EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS
Fair market value of common stock	$ 19
Fair market value of common stock		$ 19	$ 18.96	$ 17.66	$ 32.16	$ 18.47
Volatility	36.70%	37.10%	37.10%	36.80%	36.80%	37.40%
Expected term (in years)	6 years 6 months	5 years	5 years	6 years	6 years	5 years
Risk-free interest rate	0.40%	0.90%	0.80%	0.40%	0.40%	1.30%

EMPLOYEE BENEFIT AND DEFERRE_13

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - Restricted Stock Units (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Compensation plans:
Compensation expense	$ 26,160	$ 147,904	$ 9,460
Granted (in units)	59,000
Units
Balance, Bgn (in units)	670,000
Granted (in units)	59,000
Vested (in units)	(363,000)
Forfeited (in units)	(40,000)
Balance, End (in units)		670,000
Weighted Average Per Share
Balance, Bgn (in dollars per share)	$ 19
Granted (in dollars per share)	17.66
Vested (in dollars per share)	19
Forfeited (in dollars per share)	$ 19
Balance, End (in dollars per share)		$ 19
Restricted Stock Units
Compensation plans:
Compensation expense	$ 2,964	$ 171
Unrecognized compensation cost	$ 11,222
Unrecognized compensation expense period	3 years 2 months 12 days
Granted (in units)	478	101,000
Units
Balance, Bgn (in units)	101
Granted (in units)	478	101,000
Vested (in units)	(15)
Forfeited (in units)	(34)
Balance, End (in units)	530	101
Weighted Average Per Share
Balance, Bgn (in dollars per share)	$ 23.80
Granted (in dollars per share)	27.07	$ 23.80
Vested (in dollars per share)	29.67
Forfeited (in dollars per share)	25.18
Balance, End (in dollars per share)	$ 26.49	$ 23.80
Restricted Stock Units | Minimum
Compensation plans:
Service requirement (in years)	1 year
Restricted Stock Units | Maximum
Compensation plans:
Service requirement (in years)	4 years
PSU
Compensation plans:
Compensation expense	$ 0
Grant date fair value	$ 17,779
PSU | Taxamo
Compensation plans:
Granted (in units)	1,007,000
Units
Granted (in units)	1,007,000

EMPLOYEE BENEFIT AND DEFERRE_14

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - Restricted Stock Awards (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	Jul. 28, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Units
Balance, Bgn (in units)		670
Granted (in units)		59
Vested (in units)		(363)
Forfeited (in units)		(40)
Balance, End (in units)			670
Weighted Average Per Share
Balance, Bgn (in dollars per share)		$ 19
Granted (in dollars per share)		17.66
Vested (in dollars per share)		19
Forfeited (in dollars per share)		$ 19
Balance, End (in dollars per share)			$ 19
Stock-based compensation expense		$ 26,160	$ 147,904	$ 9,460
Compensation expense		$ 26,160	147,904	$ 9,460
Restricted Stock Awards
Units
Granted (in units)	694
Vested (in units)		(21)
Forfeited (in units)		(3)
Balance, End (in units)		326
Weighted Average Per Share
Granted (in dollars per share)		$ 19
Vested (in dollars per share)		19
Forfeited (in dollars per share)		19
Balance, End (in dollars per share)		$ 18.76
Compensation expense		$ 5,126	$ 4,284
Unrecognized compensation cost		$ 4,013
Unrecognized compensation expense period		1 year 9 months 18 days
Restricted Stock Awards | Maximum
Compensation plans:
Service requirement (in years)		4 years

EMPLOYEE BENEFIT AND DEFERRE_15

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - Employee Stock Purchase Plan (Details) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Compensation plans:
Compensation expense	$ 26,160	$ 147,904	$ 9,460
ESPP
Compensation plans:
Purchase price as a percent of fair value	85.00%
Reserved for issuance		1,000
Maximum issuance (as a percentage of outstanding)	1.00%
Maximum issuance (in shares)	16,000
Compensation expense	$ 537	$ 326
Unrecognized compensation cost	$ 233	$ 218

EMPLOYEE BENEFIT AND DEFERRE_16

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - ESPP - Option-pricing model key input assumptions (Details) - $ / shares	May 31, 2022	Nov. 30, 2021	May 31, 2021	Nov. 30, 2020	Jul. 28, 2020	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2021
Fair Value Assumptions and Methodology
Fair market value of common stock						$ 19	$ 18.96	$ 17.66	$ 32.16	$ 18.47
Volatility					36.70%	37.10%	37.10%	36.80%	36.80%	37.40%
Expected term (in years)					6 years 6 months	5 years	5 years	6 years	6 years	5 years
Risk-free interest rate					0.40%	0.90%	0.80%	0.40%	0.40%	1.30%
ESPP
Compensation plans:
Discount										15.00%
Offering Period										6 months
ESPP | Initial Public Offering
Fair Value Assumptions and Methodology
Fair market value of common stock	$ 17.38	$ 18.89	$ 25.83	$ 19
Volatility	37.30%	35.10%	35.10%	35.00%
Expected term (in years)	6 months	6 months	6 months	3 months 18 days
Risk-free interest rate	0.10%	0.10%	0.10%	0.10%

EMPLOYEE BENEFIT AND DEFERRE_17

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - Stock based compensation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Allocation of costs
Compensation expense	$ 26,160	$ 147,904	$ 9,460
SAR
Allocation of costs
Compensation expense	16,023	143,123	$ 9,460
Amended Options
Allocation of costs
Compensation expense	1,510
Restricted Stock Units
Allocation of costs
Compensation expense	2,964	171
Restricted Stock Awards
Allocation of costs
Compensation expense	5,126	4,284
ESPP
Allocation of costs
Compensation expense	$ 537	$ 326

EMPLOYEE BENEFIT AND DEFERRE_18

EMPLOYEE BENEFIT AND DEFERRED COMPENSATION PLANS - Stock based compensation, comprehensive income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Allocation of costs
Compensation expense	$ 26,160	$ 147,904	$ 9,460
Research and development
Allocation of costs
Compensation expense	2,620	14,694	946
Selling and marketing
Allocation of costs
Compensation expense	6,371	29,551	1,892
General and administrative
Allocation of costs
Compensation expense	12,185	67,524	4,257
Software subscriptions
Allocation of costs
Compensation expense	2,336	14,663	946
Services
Allocation of costs
Compensation expense	$ 2,648	$ 21,472	$ 1,419

RELATED PARTIES (Details)

RELATED PARTIES (Details)	Dec. 31, 2020USD ($)
RELATED PARTIES
Outstanding amount	$ 0

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Operating Leases
2021	$ 4,593
2022	4,459
2023	4,464
2024	4,382
2026	4,477
Thereafter	8,054
Total lease payments	$ 30,429
Finance Leases
2021		$ 915
2022		230
Total Lease Payments		1,145
Less amount representing interest		(38)
Present value of minimum lease payments		1,107
Less current portion		(882)
Capital lease obligations, net of current portion		$ 225

INCOME TAXES - Geography (Detai

INCOME TAXES - Geography (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
INCOME TAXES
U.S.	$ 5,608	$ (107,959)	$ 32,131
Foreign	(9,534)	90	(1,229)
(Loss) income before income taxes	$ (3,926)	$ (107,869)	$ 30,902

INCOME TAXES - Benefit (Expense

INCOME TAXES - Benefit (Expense) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Current income taxes:
State and local			$ 155	$ 617	$ 578
Foreign			468	94	115
Total current			623	711	693
Deferred income taxes:
Federal			(1,849)	(27,076)
State and local			(7)	(6,491)	(677)
Foreign			(1,214)	68	(171)
Total deferred		$ 35,860	3,116	33,499	848
Deferred income tax expense benefit excluding exchange differences			(3,070)
Income tax benefit (expense)	$ 34,629	$ 35,364	$ 2,447	$ 32,788	$ 155

INCOME TAXES - Reconciliation (

INCOME TAXES - Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
INCOME TAXES
Loss before income taxes			$ (3,926)	$ (107,869)	$ 30,902
Income tax benefit from translation adjustments and revaluations			89	55
Taxes:
U.S. federal income tax at statutory rate			(825)	(22,652)	6,489
State income taxes			678	(1,811)	(98)
Tax effect of S-Corporation status				21,325	(6,489)
Impact of change in tax status				(25,396)
Stock based compensation expense			(4,550)	(5,809)
Impact of foreign operations			954	(56)	(57)
Return to provision adjustments			(464)
Transaction costs			1,082
US taxation of foreign earnings			144	81
Nondeductible compensation			682	883
Tax credits			(488)	(44)
Change in valuation allowance			373	109
Profit sharing deduction			(46)
Other permanent items, net			13	582
Income tax benefit (expense)	$ (34,629)	$ (35,364)	$ (2,447)	$ (32,788)	$ (155)
Tax Rate (Percentage)
U.S. federal income tax at statutory rate			21.00%	21.00%	21.00%
State income taxes			(17.30%)	1.70%	(0.30%)
Tax effect of S-Corporation status				(19.80%)	(21.00%)
Impact of change in tax status				23.50%
Stock based compensation			115.90%	5.40%
Impact of foreign operations			(24.30%)	0.10%	(0.20%)
Return to provision adjustments			11.80%
Transaction costs			(27.60%)
US taxation of foreign earnings			(3.70%)	(0.10%)
Nondeductible compensation			(17.40%)	(0.80%)
Tax credits			12.40%	0.00%
Change in valuation allowance			(9.50%)	(0.10%)
Profit sharing deduction			1.20%
Other permanent items, net			(0.20%)	(0.50%)
Taxes and effective tax rate			62.30%	30.40%	(0.50%)
Deferred tax benefit related to the remeasurement				$ 25,396

INCOME TAXES - Net deferred tax

INCOME TAXES - Net deferred tax assets (liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020
Deferred tax assets:
Deferred revenue	$ 3,788				$ 3,189
State operating loss carry forwards	3,894				2,595
Federal and foreign loss carry forwards	21,617				13,388
Accrued expenses	2,023				2,324
Accrued variable compensation	3,110				3,414
Deferred and stock-based compensation	24,971				29,188
Operating lease liabilities	7,204				2,429
Tax credits	532				44
Other	53				303
Deferred tax assets	67,192				56,874
Valuation allowance	(1,839)				(1,507)
Total deferred tax assets	65,353				55,367
Deferred tax liabilities:
Depreciation and amortization	(26,269)				(19,998)
Prepaid expenses	(1,329)				(1,557)
Right of use asset	(5,120)
Deferred tax liabilities	(32,718)				(21,555)
Classification in the consolidated balance sheets
Deferred income tax asset	35,298	$ 36,672	$ 36,429	$ 34,229	33,830	$ 36,296
Net deferred tax asset	32,635				33,812
Deferred income tax asset
Classification in the consolidated balance sheets
Deferred income tax asset	35,298				33,830
Deferred other liabilities
Classification in the consolidated balance sheets
Deferred other liabilities	$ (2,663)				$ (18)

INCOME TAXES - Carryforwards (D

INCOME TAXES - Carryforwards (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Operating loss carryforwards
Incremental valuation allowances	$ 1,839	$ 1,507
Foreign
Operating loss carryforwards
Operating Loss Carryforwards	15,318
Non operating loss carryforwards	55
U.S. Federal
Operating loss carryforwards
Operating Loss Carryforwards	89,594
State and local
Operating loss carryforwards
Operating Loss Carryforwards	71,013
Incremental valuation allowances
Operating loss carryforwards
Incremental valuation allowances	$ 322	$ 1,461

SUBSEQUENT EVENTS (Details)

SUBSEQUENT EVENTS (Details) - Subsequent event $ in Thousands	Mar. 08, 2022USD ($)
Subsequent events:
Outstanding borrowings	$ 0
New Term Loan
Subsequent events:
Face amount	$ 50,000
New Term Loan | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Subsequent events:
Applicable margin (as a percent)	1.00%
Amended Line of Credit
Subsequent events:
Revolving credit commitment, aggregate amount	$ 200,000
Amended Line of Credit | Base rate
Subsequent events:
Applicable margin (as a percent)	0.00%