CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
OPERATING ACTIVITIES:
Net loss	$ (31,819)	$ (25,325)	$ (57,949)
Adjustments to reconcile net loss to net cash provided by operating activities:
(Recovery) provision for bad debt	(1,097)	1,135	4,532	[1]
Depreciation and amortization	47,479	44,810	37,274
Amortization of right-of-use asset	9,289	8,151
Stock-based compensation expense	43,290	10,321	4,849
Fair value changes in financial instruments	(3,396)	2,195	20,319
Fair value changes in business acquisition contingencies	(3,227)	24,372	12,942
Deferred income taxes	2,250	1,709	851
Debt extinguishment costs		4,052	1,810
Other	349	(195)	278
Changes in operating assets and liabilities—net of acquisitions:
Accounts receivable and contract assets	4,394	(36,164)	(19,202)
Prepaid expenses and other current assets	(1,763)	(1,148)	(4,137)
Accounts payable and other accrued liabilities	(9,878)	23,996	601
Accrued payroll and benefits	(6,830)	3,244	6,072
Payment of contingent consideration	(19,457)	(15,628)	(6,390)
Change in operating leases	(8,935)	(7,944)
Net cash (used in) provided by operating activities	20,649	37,581	1,850
INVESTING ACTIVITIES:
Proceeds received from corporate owned insurance	329	413	0
Purchases of property and equipment	(10,002)	(6,987)	(7,756)
(Payment) collection of purchase price true ups	(389)	(9,336)	1,939
Cash paid for acquisitions—net of cash acquired	(28,625)	(55,731)	(173,923)
Net cash used in investing activities	(38,687)	(71,641)	(179,740)
FINANCING ACTIVITIES:
Proceeds from line of credit		109,000	104,390
Payments on line of credit		(109,000)	(201,980)
Proceeds from term loans		175,000	175,000
Repayment of term loans	(8,750)	(173,905)	(50,195)
Payment of contingent consideration and other purchase price true ups	(11,107)	(9,865)	(6,004)
Repayment of finance leases	(3,967)	(2,711)	(2,848)
Proceeds from issuance of common stock in public offerings, net of issuance costs		169,783	161,288
Payments of deferred offering costs	(183)	(446)	(4,164)
Debt issuance cost		(2,590)	(4,866)
Proceeds from issuance of common stock for exercised stock options	1,643	7,237	408
Issuance of series A-2 preferred stock and warrant, net of issuance costs			173,664
Redemption of the series A-1 preferred stock			(131,821)
Dividend payment to the series A-2 shareholders	(16,400)	(16,400)	(6,970)
Net cash (used in) provided by financing activities	(38,764)	146,103	205,902
CHANGE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	(56,802)	112,043	28,012
Foreign exchange impact on cash balance	(111)	(183)	(15)
CASH, CASH EQUIVALENTS AND RESTRICTED CASH:
Beginning of year	146,741	34,881	6,884
End of year	89,828	146,741	34,881
SUPPLEMENTAL DISCLOSURES OF CASH FLOWS INFORMATION:
Cash paid for interest, net	6,514	5,012	11,947
Cash paid for income tax, net	789	412	171
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING ACTIVITIES:
Preferred stock deemed dividend—net of return from holders			24,341
Redemption of preferred stock in common shares			26,801
Accrued purchases of property and equipment	2,261	790	432
Property and equipment purchased under finance leases	5,061	1,766	2,113
Accretion of the redeemable series A-1 preferred stock to redeemable value			17,601
Common stock issued to acquire new businesses		8,320	25,000
Acquisitions unpaid contingent consideration	$ 8,255	35,800	$ 54,457
Acquisitions contingent consideration paid in shares		26,084
Offering costs included in accounts payable and other accrued liabilities		$ 183

[1] During the first quarter of 2020, there was a global outbreak of a new strain of coronavirus, COVID-19. The COVID-19 pandemic added uncertainty to the collectability of certain receivables, particularly in industries hard hit by the pandemic. As a result, the Company recorded $6.3 million of bad debt reserve during the first quarter of 2020. The bad debt adjustment included a $5.5 million reserve for one customer in the Company’s Remediation and Reuse segment in which management concluded to discontinue select service lines as of June 30, 2020 (Note 21).