Willdan (WLDN) 10-Q 4 Aug 22 2022 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jul. 01, 2022	Aug. 03, 2022
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Jul. 01, 2022
Entity File Number	001-33076
Entity Registrant Name	WILLDAN GROUP, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	14-1951112
Entity Address, Address Line One	2401 East Katella Avenue
Entity Address, Address Line Two	Suite 300
Entity Address, City or Town	Anaheim
Entity Address, Postal Zip Code	92806
Entity Address, State or Province	CA
City Area Code	800
Local Phone Number	424-9144
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	WLDN
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		13,282,133
Current Fiscal Year End Date	--12-30
Document Fiscal Period Focus	Q2
Document Fiscal Year Focus	2022
Entity Central Index Key	0001370450
Amendment Flag	false

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jul. 01, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 5,811	$ 11,221
Accounts receivable, net of allowance for doubtful accounts of $751 and $1,115 at July 1, 2022 and December 31, 2021, respectively	60,301	67,211
Contract assets	61,177	59,288
Other receivables	6,231	6,267
Prepaid expenses and other current assets	4,864	4,972
Total current assets	138,384	148,959
Equipment and leasehold improvements, net	19,382	16,757
Goodwill	130,124	130,124
Right-of-use assets	13,387	15,177
Other intangible assets, net	47,024	52,713
Other assets	13,891	13,843
Deferred income taxes, net	19,691	16,849
Total assets	381,883	394,422
Current liabilities:
Accounts payable	27,813	36,672
Accrued liabilities	34,994	35,680
Contingent consideration payable	943	10,206
Contract liabilities	11,410	13,499
Notes payable	16,019	15,036
Finance lease obligations	891	539
Lease liability	5,435	5,575
Total current liabilities	97,505	117,207
Contingent consideration payable		832
Notes payable	97,121	85,538
Finance lease obligations, less current portion	1,413	778
Lease liability, less current portion	8,956	10,768
Other noncurrent liabilities	78	78
Total liabilities	205,073	215,201
Commitments and contingencies
Stockholders' equity:
Preferred stock, $0.01 par value, 10,000 shares authorized, no shares issued and outstanding
Common stock, $0.01 par value, 40,000 shares authorized; 13,215 and 12,804 shares issued and outstanding at July 1, 2022 and December 31, 2021, respectively	132	128
Additional paid-in capital	172,678	167,032
Accumulated other comprehensive loss		(38)
Retained earnings	4,000	12,099
Total stockholders' equity	176,810	179,221
Total liabilities and stockholders' equity	$ 381,883	$ 394,422

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jul. 01, 2022	Dec. 31, 2021
Accounts receivable, allowance for doubtful accounts
Accounts receivable, allowance for doubtful accounts	$ 751	$ 1,115
Preferred stock
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	40,000,000	40,000,000
Common stock, shares issued (in shares)	13,215,000	12,804,000
Common stock, shares outstanding (in shares)	13,215,000	12,804,000

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2022	Jul. 02, 2021	Jul. 01, 2022	Jul. 02, 2021
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Contract revenue	$ 102,645	$ 84,154	$ 194,483	$ 163,240
Direct costs of contract revenue (inclusive of directly related depreciation and amortization):
Salaries and wages	21,284	16,366	40,094	32,186
Subcontractor services and other direct costs	49,771	36,902	91,439	68,036
Total direct costs of contract revenue	71,055	53,268	131,533	100,222
General and administrative expenses:
Salaries and wages, payroll taxes and employee benefits	20,439	18,712	39,796	38,156
Facilities and facility related	2,373	2,379	4,771	5,022
Stock-based compensation	1,714	5,933	5,019	10,139
Depreciation and amortization	4,426	4,224	8,835	8,411
Other	7,936	6,710	15,435	12,551
Total general and administrative expenses	36,888	37,958	73,856	74,279
Income (Loss) from operations	(5,298)	(7,072)	(10,906)	(11,261)
Other income (expense):
Interest expense, net	(1,030)	(1,099)	(1,781)	(2,163)
Other, net	329	(93)	526	(64)
Total other expense, net	(701)	(1,192)	(1,255)	(2,227)
Income (Loss) before income taxes	(5,999)	(8,264)	(12,161)	(13,488)
Income tax (benefit) expense	(1,673)	(3,663)	(4,062)	(5,121)
Net income (loss)	(4,326)	(4,601)	(8,099)	(8,367)
Other comprehensive income (loss):
Unrealized gain (loss) on derivative contracts, net of tax		104	38	232
Comprehensive income (loss)	$ (4,326)	$ (4,497)	$ (8,061)	$ (8,135)
Earnings (loss) per share:
Basic (in dollars per share)	$ (0.33)	$ (0.37)	$ (0.63)	$ (0.68)
Diluted (in dollars per share)	$ (0.33)	$ (0.37)	$ (0.63)	$ (0.68)
Weighted-average shares outstanding:
Basic (in shares)	13,016	12,421	12,901	12,284
Diluted (in shares)	13,016	12,421	12,901	12,284

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Total
Balances at Jan. 01, 2021	$ 122	$ 149,014	$ (488)	$ 20,516	$ 169,164
Balances (in shares) at Jan. 01, 2021	12,160
Increase (Decrease) in Stockholders' Equity
Shares of common stock issued in connection with employee stock purchase plan	$ 1	1,384			1,385
Shares of common stock issued in connection with employee stock purchase plan (in shares)	66
Shares of common stock issued in connection with incentive stock plan		527			527
Shares of common stock issued in connection with incentive stock plan (in shares)	27
Shares used to pay taxes on stock grants		(12)			(12)
Issuance of restricted stock award and units	$ 2	(3)			(1)
Issuance of restricted stock award and units (in shares)	255
Stock-based compensation expense		4,206			4,206
Net income (loss)				(3,766)	(3,766)
Other comprehensive income			128		128
Balances at Apr. 02, 2021	$ 125	155,116	(360)	16,750	171,631
Balances (in shares) at Apr. 02, 2021	12,508
Balances at Jan. 01, 2021	$ 122	149,014	(488)	20,516	169,164
Balances (in shares) at Jan. 01, 2021	12,160
Increase (Decrease) in Stockholders' Equity
Net income (loss)					(8,367)
Balances at Jul. 02, 2021	$ 127	158,793	(256)	12,149	170,813
Balances (in shares) at Jul. 02, 2021	12,713
Balances at Apr. 02, 2021	$ 125	155,116	(360)	16,750	171,631
Balances (in shares) at Apr. 02, 2021	12,508
Increase (Decrease) in Stockholders' Equity
Shares of common stock issued in connection with incentive stock plan	$ 1	850			851
Shares of common stock issued in connection with incentive stock plan (in shares)	77
Shares used to pay taxes on stock grants	$ (1)	(3,104)			(3,105)
Shares used to pay taxes on stock grants (in shares)	(79)
Issuance of restricted stock award and units	$ 2	(2)
Issuance of restricted stock award and units (in shares)	207
Stock-based compensation expense		5,933			5,933
Net income (loss)				(4,601)	(4,601)
Other comprehensive income			104		104
Balances at Jul. 02, 2021	$ 127	158,793	(256)	12,149	170,813
Balances (in shares) at Jul. 02, 2021	12,713
Balances at Dec. 31, 2021	$ 128	167,032	(38)	12,099	$ 179,221
Balances (in shares) at Dec. 31, 2021	12,804				12,804
Increase (Decrease) in Stockholders' Equity
Shares of common stock issued in connection with employee stock purchase plan	$ 1	1,560			$ 1,561
Shares of common stock issued in connection with employee stock purchase plan (in shares)	52
Shares of common stock issued in connection with incentive stock plan		23			23
Shares of common stock issued in connection with incentive stock plan (in shares)	4
Shares used to pay taxes on stock grants		(837)			(837)
Shares used to pay taxes on stock grants (in shares)	(27)
Issuance of restricted stock award and units	$ 3	(3)
Issuance of restricted stock award and units (in shares)	373
Stock-based compensation expense		3,305			3,305
Net income (loss)				(3,773)	(3,773)
Other comprehensive income			38		38
Balances at Apr. 01, 2022	$ 132	171,080		8,326	179,538
Balances (in shares) at Apr. 01, 2022	13,206
Balances at Dec. 31, 2021	$ 128	167,032	$ (38)	12,099	$ 179,221
Balances (in shares) at Dec. 31, 2021	12,804				12,804
Increase (Decrease) in Stockholders' Equity
Net income (loss)					$ (8,099)
Balances at Jul. 01, 2022	$ 132	172,678		4,000	$ 176,810
Balances (in shares) at Jul. 01, 2022	13,215				13,215
Balances at Apr. 01, 2022	$ 132	171,080		8,326	$ 179,538
Balances (in shares) at Apr. 01, 2022	13,206
Increase (Decrease) in Stockholders' Equity
Shares used to pay taxes on stock grants		(116)			(116)
Shares used to pay taxes on stock grants (in shares)	(5)
Issuance of restricted stock award and units (in shares)	14
Stock-based compensation expense		1,714			1,714
Net income (loss)				(4,326)	(4,326)
Balances at Jul. 01, 2022	$ 132	$ 172,678		$ 4,000	$ 176,810
Balances (in shares) at Jul. 01, 2022	13,215				13,215

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jul. 01, 2022	Jul. 02, 2021
Cash flows from operating activities:
Net income (loss)	$ (8,099)	$ (8,367)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	8,835	8,411
Deferred income taxes, net	(2,842)	(3,041)
(Gain) loss on sale/disposal of equipment	(69)	(25)
Provision for doubtful accounts	107	342
Stock-based compensation	5,019	10,139
Accretion and fair value adjustments of contingent consideration	111	751
Changes in operating assets and liabilities, net of effects from business acquisitions:
Accounts receivable	6,803	2,946
Contract assets	(1,889)	(4,266)
Other receivables	36	984
Prepaid expenses and other current assets	225	1,525
Other assets	(48)	5,000
Accounts payable	(8,859)	(13,311)
Accrued liabilities	(648)	(2,712)
Contract liabilities	(2,089)	1,020
Right-of-use assets	(162)	(104)
Net cash provided by operating activities	(3,569)	(708)
Cash flows from investing activities:
Purchase of equipment and leasehold improvements	(4,344)	(3,100)
Proceeds from sale of equipment	73	43
Net cash (used in) provided by investing activities	(4,271)	(3,057)
Cash flows from financing activities:
Payments on contingent consideration	(10,206)	(6,616)
Payments on notes payable	(1,051)	(1,541)
Borrowings under term loan facility and line of credit	20,000
Repayments under term loan facility and line of credit	(6,500)	(6,500)
Principal payments on finance leases	(444)	(214)
Proceeds from stock option exercise	23	1,378
Proceeds from sales of common stock under employee stock purchase plan	1,561	1,385
Cash used to pay taxes on stock grants	(953)	(3,117)
Restricted Stock Award and Units		(1)
Net cash (used in) provided by financing activities	2,430	(15,226)
Net increase (decrease) in cash and cash equivalents	(5,410)	(18,991)
Cash and cash equivalents at beginning of period	11,221	28,405
Cash and cash equivalents at end of period	5,811	9,414
Cash paid during the period for:
Interest	1,584	1,961
Income taxes	413	(1,669)
Supplemental disclosures of noncash investing and financing activities:
(Gain) loss on cash flow hedge valuations, net of tax	38	232
Equipment acquired under finance leases	$ 1,431	$ 575

ORGANIZATION AND OPERATIONS OF

ORGANIZATION AND OPERATIONS OF THE COMPANY	6 Months Ended
	Jul. 01, 2022
ORGANIZATION AND OPERATIONS OF THE COMPANY
ORGANIZATION AND OPERATIONS OF THE COMPANY	1. ORGANIZATION AND OPERATIONS OF THE COMPAN Y Willdan Group, Inc. (“Willdan” or the “Company”) is a provider of professional, technical and consulting services to utilities, private industry, and public agencies at all levels of government. As resources and infrastructures undergo continuous change, the Company helps organizations and their communities evolve and thrive by providing a wide range of technical services for energy solutions and government infrastructure. Through engineering, program management, policy advisory, and software and data management, the Company designs and delivers trusted, comprehensive, innovative, and proven solutions to improve efficiency, resiliency, and sustainability in energy and infrastructure. The Company’s broad portfolio of services operates within two financial reporting segments: (1) Energy and (2) Engineering and Consulting. The interfaces and synergies between these segments are important elements of the Company’s strategy to design and deliver trusted, comprehensive, innovative, and proven solutions for its customers. ​ The accounting policies followed by the Company are set forth in Part II, Item 8, Note 1, Organization and Operations of the Company Fiscal Years The Company operates and reports its annual financial results based on 52 or 53-week periods ending on the Friday closest to December 31. The Company operates and reports its quarterly financial results based on the 13-week period ending on the Friday closest to June 30, September 30, and December 31 and the 13 or 14-week period ending on the Friday closest to March 31, as applicable. Fiscal year 2022, which ends on December 30, 2022, will be comprised of 52 weeks, with all quarters consisting of 13 weeks each. Fiscal year 2021, which ended on December 31, 2021, was comprised of 52 weeks, with all quarters consisting of 13 weeks each. All references to years in the notes to consolidated financial statements represent fiscal years. Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements. Estimates also affect the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates. Historical and Current Impact of Covid-19 The coronavirus (“Covid-19”) pandemic and efforts to limit its spread negatively impacted the Company’s operations during its fiscal year 2020 and continued to impact the Company, albeit to a lesser extent, during fiscal year 2021. In California and New York, the states in which the Company has historically derived a majority of its revenue, mandatory shutdown orders were issued in March 2020 followed by phased re-openings that began in May 2020, followed by periods of curtailments as a result of resurgences of Covid-19 cases, and subsequent re-openings through 2020 and 2021. The Company’s largest program for the Los Angeles Department of Water and Power (“LADWP”) resumed in the third quarter of fiscal 2021 and was the Company’s last program suspended due to Covid-19. In addition, through fiscal year 2020 and 2021, none of the Company’s contracts were cancelled due to Covid-19. ​ ​ Asset and liability valuation and other estimates used in preparation of financial statements not long-lived assets Impact on Clients and Subcontractors and Other Risks The Company primarily works for utilities, municipalities and other public agencies. Should there be a resurgence related to Covid-19, some of these customers could experience significant budget shortfalls for the current year and beyond as a result of the measures taken to mitigate the resurgence effects of the Covid-19 pandemic and/or revenue shortfalls as a result of reduced economic activity. Although none of the Company’s contracts with governmental or public agencies were materially modified during its fiscal year 2020 or fiscal year 2021, these potential budget deficits could result in delayed funding for existing contracts with the Company, postponements of new contracts or price concessions. Further, most of the Company’s clients are not committed to purchase any minimum amount of services, as the Company agreements with them are based on a “purchase order” or “master service agreement” model. As a result, they may discontinue utilizing some or all of the Company’s services with little or no notice. In addition, the Company relies on subcontractors and material suppliers to complete a substantial portion of its work, especially in its Energy segment. If the Company’s significant subcontractors and material suppliers suffer significant economic harm and must limit or cease operations or file for bankruptcy as a result of the current economic slowdown, the Company’s subcontractors and material suppliers may not be able to fulfill their contractual obligations satisfactorily and the Company may not have the ability to select its subcontractors and material suppliers of choice for new contracts. If the Company’s subcontractors and material suppliers are not able to fulfill their contractual obligations, it could result in a significant increase in costs for the Company to complete the projects or cause significant delays to the realization of revenues under those projects. The ultimate impact of Covid-19 on the Company’s financial condition and results of operations will depend on all of the factors noted above, including other factors that the Company may not be able to forecast at this time. See the risk factor “ The Covid-19 pandemic and health and safety measures intended to slow its spread have adversely affected, and may continue to adversely affect, our business, results of operations and financial condition.

RECENT ACCOUNTING PRONOUNCEMENT

RECENT ACCOUNTING PRONOUNCEMENTS	6 Months Ended
	Jul. 01, 2022
RECENT ACCOUNTING PRONOUNCEMENTS
RECENT ACCOUNTING PRONOUNCEMENTS	2. RECENT ACCOUNTING PRONOUNCEMENTS Accounting Pronouncements Recently Adopted In March 2020, the FASB issued ASU No. 2020-04, “Reference Rate Reform (Topic 848): facilitation of the Effects of Reference Rate Reform on Financial Reporting” (“ASU 2020-04”). ASU 2020-04 provides optional expedients and exceptions for applying U.S. GAAP to contract modifications and hedging relationships that reference LIBOR or another reference rate expected to be discontinued because of reference rate reform. ASU 2020-04 provides, among other things, guidance that modifications of contracts within the scope of Topic 470, Debt, should be accounted for by prospectively adjusting the effective interest rate; modifications of contracts within the scope of Topic 840, Leases, should be accounted for as a continuation of the existing contract; and, changes in the critical terms of hedging relationships, caused by reference rate reform, should not result in the de-designation of the instrument, provided certain criteria are met. In January 2021, the FASB issued ASU No. 2021-01, “Reference Rate Reform (Topic 848) - Scope” (“ASU 2021-01”). ASU 2021-01 clarifies the scope and application of ASU 2020-04 and permits entities, among other things, to elect certain optional expedients and exceptions when accounting for derivative contracts and certain hedging relationships affected by changes in the interest rates used for discounting cash flows. The Company adopted this standard effective March 8, 2022 . The Company’s previous exposure to LIBOR rates included its credit facilities and swap agreement. The adoption of this standard did not have a material impact to the Company’s Condensed Consolidated Financial Statements. ​

REVENUES

REVENUES	6 Months Ended
	Jul. 01, 2022
REVENUES
REVENUES	3. REVENUES The Company enters into contracts with its clients that contain various types of pricing provisions, including fixed price, time-and-materials, and unit-based provisions. The Company recognizes revenues in accordance with ASU 2014-09, Revenue from Contracts with Customer, codified as ASC Topic 606 and the related amendments (collectively “ASC 606”). As such, the Company identifies a contract with a customer, identifies the performance obligations in the contract, determines the transaction price, allocates the transaction price to each performance obligation in the contract and recognizes revenues when (or as) the Company satisfies a performance obligation. The following table reflects the Company’s two reportable segments and the types of contracts that each most commonly enters into for revenue generating activities. ​ Segment Contract Type Revenue Recognition Method ​ Time-and-materials Time-and-materials Energy Unit-based Unit-based ​ Software license Unit-based ​ Fixed price Percentage-of-completion ​ Time-and-materials Time-and-materials Engineering and Consulting Unit-based Unit-based ​ Fixed price Percentage-of-completion ​ Revenue on the vast majority of the Company’s contracts is recognized over time because of the continuous transfer of control to the customer. Revenue on fixed price contracts is recognized on the percentage-of-completion method based generally on the ratio of direct costs incurred-to-date to estimated total direct costs at completion. The Company uses the percentage-of-completion method to better match the level of work performed at a certain point in time in relation to the effort that will be required to complete a project. In addition, the percentage-of-completion method is a common method of revenue recognition in the Company’s industry. Many of the Company’s fixed price contracts involve a high degree of subcontracted fixed price effort and are relatively short in duration, thereby lowering the risks of not properly estimating the percent complete. Revenue on time-and-materials and unit-based contracts is recognized as the work is performed in accordance with the specific rates and terms of the contract. The Company recognizes revenues for time-and-materials contracts based upon the actual hours incurred during a reporting period at contractually agreed upon rates per hour and also includes in revenue all reimbursable costs incurred during a reporting period. Certain of the Company’s time-and-materials contracts are subject to maximum contract values and, accordingly, when revenue is expected to exceed the maximum contract value, these contracts are generally recognized under the percentage-of-completion method, consistent with fixed price contracts. For unit-based contracts, the Company recognizes the contract price of units of a basic production product as revenue when the production product is delivered during a period. Revenue for amounts that have been billed but not earned is deferred, and such deferred revenue is referred to as contract liabilities in the accompanying condensed consolidated balance sheets. The Company also derives revenue from software licenses and professional services and maintenance fees. In accordance with ASC 606, the Company performs an assessment of each contract to identify the performance obligations, determine the overall transaction price for the contract, allocate the transaction price to the performance obligations, and recognize the revenue when the performance obligations are satisfied. The Company utilizes the residual approach by which it estimates the standalone selling price by reference to the total transaction price less the sum of the observable standalone selling prices of other goods or services promised in the contract. The software license revenue is typically recognized at a point in time when control is transferred to the client, which is defined as the point in time when the client can use and benefit from the license. The software license is delivered before related services are provided and is functional without services, updates, or technical support. Related professional services include training and support services in which the standalone selling price is determined based on an input measure of hours incurred to total estimated hours and is recognized over time, usually which is the life of the contract. To determine the proper revenue recognition method for contracts, the Company evaluates whether two or more contracts should be combined and accounted for as one single contract and whether the combined contract should be accounted for as one performance obligation. With respect to the Company’s contracts, it is rare that multiple contracts should be combined into a single performance obligation. This evaluation requires significant judgment and the decision to combine a group of contracts or separate a single contract into multiple performance obligations could change the amount of revenue and profit recorded in a given period. Contracts are considered to have a single performance obligation if the promise to transfer the individual goods or services is not separately identifiable from other promises in the contracts, which is mainly because the Company provides a significant service of integrating a complex set of tasks and components into a single project or capability. The Company may enter into contracts that include separate phases or elements. If each phase or element is negotiated separately based on the technical resources required and/or the supply and demand for the services being provided, the Company evaluates if the contracts should be segmented. If certain criteria are met, the contracts would be segmented which could result in revenues being assigned to the different elements or phases with different rates of profitability based on the relative value of each element or phase to the estimated total contract revenue. Segmented contracts may comprise up to approximately Contracts that cover multiple phases or elements of the project or service lifecycle (development, construction and maintenance and support) may be considered to have multiple performance obligations even when they are part of a single contract. For contracts with multiple performance obligations, the Company allocates the transaction price to each performance obligation using the best estimate of the standalone selling price of each distinct good or service in the contract. For the periods presented, the value of the separate performance obligations under contracts with multiple performance obligations (generally measurement and verification tasks under certain energy performance contracts) were not material. In cases where the Company does not provide the distinct good or service on a standalone basis, the primary method used to estimate standalone selling price is the expected cost plus a margin approach, under which the Company forecasts the Company’s expected costs of satisfying a performance obligation and then adds an appropriate margin for the distinct good or service. The Company provides quality of workmanship warranties to customers that are included in the sale and are not priced or sold separately or do not provide customers with a service in addition to assurance of compliance with agreed-upon specifications and industry standards. The Company does not consider these types of warranties to be separate performance obligations. In some cases, the Company has a master service or blanket agreement with a customer under which each task order releases the Company to perform specific portions of the overall scope in the service contract. Each task order is typically accounted for as a separate contract because the task order establishes the enforceable rights and obligations, and payment terms. Under ASC 606, variable consideration should be considered when determining the transaction price and estimates should be made for the variable consideration component of the transaction price, as well as assessing whether an estimate of variable consideration is constrained. For certain of the Company’s contracts, variable consideration can arise from modifications to the scope of services resulting from unapproved change orders or customer claims. Variable consideration is included in the transaction price to the extent it is probable that a significant reversal of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is resolved. The Company estimates of variable consideration and determination of whether to include estimated amounts in the transaction price are based largely on assessments of legal enforceability, the Company’s performance, and all information (historical, current and forecasted) that is reasonably available to the Company. Due to the nature of the work required to be performed on many of the Company’s performance obligations, the estimation of total revenue and cost at completion is complex, subject to many variables and requires significant judgment. As a significant change in one or more of these estimates could affect the profitability of the Company’s contracts, the Company reviews and updates the Company’s contract-related estimates regularly through a company-wide disciplined project review process in which management reviews the progress and execution of the Company’s performance obligations and the estimate at completion (“EAC”). As part of this process, management reviews information including, but not limited to, any outstanding key contract matters, progress towards completion and the related program schedule and the related changes in estimates of revenues and costs. Management must make assumptions and estimates regarding labor productivity and availability, the complexity of the work to be performed, the cost and availability of materials, the performance of subcontractors, and the availability and timing of funding from the customer, among other variables. The Company recognizes adjustments in estimated profit on contracts under the cumulative catch-up method. Under this method, the impact of the adjustment on profit recorded to date is recognized in the period the adjustment is identified. Revenue and profit in future periods of contract performance is recognized using the adjusted estimate. If at any time the estimate of contract profitability indicates an anticipated loss on the contract, the Company recognizes the full amount of estimated loss in the period it is identified. Contracts are often modified to account for changes in contract specifications and requirements. The Company considers contract modifications to exist when the modification either creates new rights or obligations or changes the existing enforceable rights or obligations. Most of the Company’s contract modifications are for goods or services that are not distinct from existing contracts due to the significant integration provided in the context of the contract and are accounted for as if they were part of the original contract. The effect of a contract modification that is not distinct from the existing contract on the transaction price and the Company’s measure of progress for the performance obligation to which it relates is recognized as an adjustment to revenue (either as an increase in or a reduction of revenue) on a cumulative catch-up basis. For contract modifications that result in the promise to deliver goods or services that are distinct from the existing contract and the increase in price of the contract is for the same amount as the standalone selling price of the additional goods or services included in the modification, the Company accounts for such contract modifications as a separate contract. The Company includes claims to vendors, subcontractors and others as a receivable and a reduction in recognized costs when enforceability of the claim is established by the contract and the amounts are reasonably estimable and probable of being recovered. The amounts are recorded up to the extent of the lesser of the amounts management expects to recover or to costs incurred. Billing practices are governed by the contract terms of each project based upon costs incurred, achievement of milestones or pre-agreed schedules. Billings do not necessarily correlate with revenue recognized using the percentage-of-completion method of revenue recognition. Direct costs of contract revenue consist primarily of that portion of technical and nontechnical salaries and wages that has been incurred in connection with revenue producing projects. Direct costs of contract revenue also include production expenses, subcontractor services and other expenses that are incurred in connection with revenue producing projects. Direct costs of contract revenue exclude that portion of technical and nontechnical salaries and wages related to marketing efforts, vacations, holidays and other time not spent directly generating revenue under existing contracts. Such costs are included in general and administrative expenses. Additionally, payroll taxes, bonuses and employee benefit costs for all Company personnel are included in general and administrative expenses in the accompanying consolidated statements of comprehensive income since no allocation of these costs is made to direct costs of contract revenue. No allocation of facilities costs is made to direct costs of contract revenue. Other companies may classify as direct costs of contract revenue some of the costs that the Company classifies as general and administrative costs. The Company expenses direct costs of contract revenue when incurred. Included in revenue and costs are all reimbursable costs for which the Company has the risk or on which the fee was based at the time of bid or negotiation. No revenue or cost is recorded for costs in which the Company acts solely in the capacity of an agent and has no risks associated with such costs. Accounts receivable are carried at original invoice amount less an estimate made for doubtful accounts based upon a review of all outstanding amounts on a quarterly basis. Management determines allowances for doubtful accounts through specific identification of amounts considered to be uncollectible and potential write-offs, plus a non-specific allowance for other amounts for which some potential loss has been determined to be probable based on current and past experience. The Company’s historical credit losses have been minimal with governmental entities and large public utilities, but disputes may arise related to these receivable amounts. Accounts receivable are written off when deemed uncollectible. Recoveries of accounts receivable previously written off are recorded when received. Retainage, included in contract assets, represents amounts withheld from billings to the Company’s clients pursuant to provisions in the contracts and may not be paid to the Company until specific tasks are completed or the project is completed and, in some instances, for even longer periods. As of July 1, 2022 and December 31, 2021, contract assets included retainage of approximately $6.4 million and $4.5 million, respectively. ​

SUPPLEMENTAL FINANCIAL STATEMEN

SUPPLEMENTAL FINANCIAL STATEMENT DATA	6 Months Ended
	Jul. 01, 2022
SUPPLEMENTAL FINANCIAL STATEMENT DATA
SUPPLEMENTAL FINANCIAL STATEMENT DATA	4. SUPPLEMENTAL FINANCIAL STATEMENT DATA Accounts Receivable From time to time, in connection with factoring agreements, the Company sells trade accounts receivable without recourse to third party purchasers in exchange for cash. During the six months ended July 1, 2022, the Company did not sell any trade accounts receivable. During the six months ended July 2, 2021, the Company sold trade accounts receivable and received cash proceeds of $8.0 million. The discounts on the trade accounts receivable sold were $0.8 million and were recorded within “Other, net” in other income (expense) in the condensed consolidated financial statements. Equipment and Leasehold Improvements ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ July 1, ​ December 31, ​ 2022 2021 ​ ​ (in thousands) Furniture and fixtures ​ $ 4,018 ​ $ 4,070 Computer hardware and software ​ 30,659 ​ 26,425 Leasehold improvements ​ 3,011 ​ 3,011 Equipment under finance leases ​ 4,541 ​ 3,286 Automobiles, trucks, and field equipment ​ 3,111 ​ 3,099 Subtotal ​ 45,340 ​ 39,891 Accumulated depreciation and amortization ​ (25,958) ​ (23,134) Equipment and leasehold improvements, net ​ $ 19,382 ​ $ 16,757 ​ Included in accumulated depreciation and amortization is $0.5 million and $0.6 million of amortization expense related to equipment held under finance leases for the six months ended July 1, 2022 and for fiscal year 2021, respectively. Accrued Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ July 1, ​ December 31, ​ 2022 2021 ​ ​ (in thousands) Accrued subcontractor costs ​ $ 22,938 ​ $ 19,727 Other ​ 4,263 ​ 2,750 Employee withholdings ​ 2,943 ​ 2,665 Compensation and payroll taxes ​ 2,546 ​ 2,244 Accrued bonuses ​ ​ 1,733 ​ ​ 7,767 Accrued workers’ compensation insurance ​ 571 ​ 527 Total accrued liabilities ​ $ 34,994 ​ $ 35,680 ​ Goodwill ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ Additional ​ Additions / ​ July 1, ​ 2021 Purchase Cost Adjustments 2022 ​ ​ (in thousands) Reporting Unit: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Energy ​ $ 129,375 ​ $ — ​ $ — ​ $ 129,375 Engineering and Consulting ​ ​ 749 ​ ​ — ​ ​ — ​ ​ 749 ​ ​ $ 130,124 ​ $ — ​ $ — ​ $ 130,124 ​ Intangible Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ July 1, 2022 ​ December 31, 2021 ​ ​ ​ ​ ​ ​ ​ ​ Gross ​ Accumulated ​ Gross ​ Accumulated ​ Amortization ​ Amount Amortization Amount Amortization Period ​ ​ (in thousands) ​ (in years) Finite: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Backlog ​ $ 7,944 ​ $ 7,655 ​ $ 7,944 ​ $ 7,222 ​ 1.0 Tradename ​ 15,911 ​ 9,993 ​ 15,911 ​ 8,997 2.5 ​ - ​ 6.0 Non-compete agreements ​ ​ 1,420 ​ ​ 1,420 ​ ​ 1,420 ​ ​ 1,413 ​ 4.0 ​ - ​ 5.0 Developed technology ​ ​ 15,810 ​ ​ 10,411 ​ ​ 15,500 ​ ​ 8,950 ​ 8.0 Customer relationships ​ ​ 58,149 ​ ​ 22,731 ​ ​ 58,149 ​ ​ 19,939 ​ 5.0 ​ - ​ 8.0 Total finite intangible assets ​ ​ 99,234 ​ ​ 52,210 ​ ​ 98,924 ​ ​ 46,521 ​ ​ ​ ​ ​ ​ In-process research and technology (1) ​ ​ — ​ ​ — ​ ​ 310 ​ ​ — ​ ​ ​ ​ ​ ​ Total intangible assets ​ $ 99,234 ​ $ 52,210 ​ $ 99,234 ​ $ 46,521 ​ ​ ​ ​ ​ ​ (1) In-process research and technology will not be amortized until put into use. ​ During the six months ended July 1, 2022, the Company reclassified $0.3 million of in-process research and technology to developed technology ​ ​

DERIVATIVE FINANCIAL INSTRUMENT

DERIVATIVE FINANCIAL INSTRUMENTS	6 Months Ended
	Jul. 01, 2022
DERIVATIVE FINANCIAL INSTRUMENTS
DERIVATIVE FINANCIAL INSTRUMENTS	5. DERIVATIVE FINANCIAL INSTRUMENTS From time to time, the Company uses certain interest rate derivative contracts to hedge interest rate exposures on its variable rate debt. The Company’s hedging program is not designated for trading or speculative purposes. The Company recognizes derivative instruments as either assets or liabilities on the accompanying consolidated balance sheets at fair value. The Company records changes in the fair value (i.e., gains or losses) of the derivatives that have been designated as cash flow hedges in its consolidated balance sheets as accumulated other comprehensive income (loss) and in its condensed consolidated statements of comprehensive (loss) income as a loss or gain on cash flow hedge valuation. On January 31, 2019, the Company entered into an interest rate swap agreement that the Company designated as cash flow hedge to fix the variable interest rate on a portion of the Company’s Term A Loan (as defined below in Note 6. “ Debt Obligations expired At its expiration, changes in the fair value of the Company’s interest rate swap agreement were immaterial to the Company’s condensed consolidated financial statements and were included in accrued liabilities in the condensed consolidated balance sheet. At its expiration, the effective portion of the Company’s interest rate swap agreement designated as a cash flow hedge was immaterial to the Company’s condensed consolidated financial statements, and all amounts were reclassified from accumulated other comprehensive income to interest expense. As of July 1, 2022, the Company had no derivative financial instruments in place. ​ ​ ​

DEBT OBLIGATIONS

DEBT OBLIGATIONS	6 Months Ended
	Jul. 01, 2022
DEBT OBLIGATIONS
DEBT OBLIGATIONS	6. DEBT OBLIGATIONS Debt obligations, excluding obligations under finance leases (see Note 7, Leases, ​ ​ ​ ​ ​ ​ ​ ​ ​ July 1, December 31, ​ ​ 2022 ​ 2021 ​ ​ (in thousands) Outstanding borrowings on Term A Loan ​ $ 70,000 ​ $ 75,000 Outstanding borrowings on Revolving Credit Facility ​ ​ — ​ ​ — Outstanding borrowings on Delayed Draw Term Loan ​ ​ 42,500 ​ ​ 24,000 Other debt agreements ​ ​ 1,110 ​ ​ 2,161 Total debt ​ ​ 113,610 ​ ​ 101,161 Issuance costs and debt discounts ​ ​ (470) ​ ​ (587) Subtotal ​ ​ 113,140 ​ ​ 100,574 Less current portion of long-term debt ​ 16,019 ​ 15,036 Long-term debt portion ​ $ 97,121 ​ $ 85,538 ​ Credit Facilities On June 26, 2019, the Company and certain of its subsidiaries entered into an Amended and Restated Credit Agreement (as amended by the First Amendment, dated as of August 15, 2019, the Second Amendment, dated as of November 6, 2019, the Third Amendment, dated as of May 6, 2020, the Fourth Amendment, dated April 30, 2021, and the Fifth Amendment, dated March 8, 2022, the “Credit Agreement”) with a syndicate of financial institutions as lenders and BMO Harris Bank, N.A. (“BMO”), as administrative agent. The Credit Agreement provides for (i) a $100.0 million secured term loan (the “Term A Loan”), (ii) up to $50.0 million in delayed draw secured term loans (the “Delayed Draw Term Loan”), and (iii) a $50.0 million secured revolving credit facility (the “Revolving Credit Facility” and, collectively with the Term A Loan and the Delayed Draw Term Loan, the “Credit Facilities”), each maturing on June 26, 2024. The Company’s obligations under the Credit Agreement are guaranteed by its present and future domestic subsidiaries, with limited exceptions. Prior to the Fourth Amendment to the Credit Agreement, dated as of April 30, 2021 (the “Fourth Amendment”), the Credit Agreement required the Company to comply with certain financial covenants, including requiring that the Company maintain a (i) total leverage ratio (the “Leverage Ratio”), defined as the ratio of total funded debt to Adjusted EBITDA (as defined in the Credit Agreement), of 6.00 to 1.00 through June 26, 2020, 7.75 to 1.00 through September 25, 2020, 7.50 to 1.00 through January 1, 2021, 6.25 to 1.00 through April 2, 2021, 4.00 to 1.00 through July 2, 2021, and 3.25 to 1.00 through October 1, 2021 and thereafter and (ii) fixed charge coverage ratio (“FCCR Ratio”), defined as the ratio of Adjusted EBITDA less Unfinanced Capital Expenditures (as defined in the Credit Agreement) to Fixed Charges (as defined in the Credit Agreement), of not less than 1.20 to 1.00, in each case tested quarterly, except during the period from May 6, 2020 until July 2, 2021 (the “Initial Covenant Relief Period”), when the maximum Leverage Ratio was increased and the covenant to maintain a minimum FCCR Ratio was replaced with a covenant to maintain a minimum Adjusted EBITDA (as defined in the Third Amendment). In addition, during the Initial Covenant Relief Period, no delayed draw term loans could be borrowed under the Credit Facilities and the Company was prohibited from engaging in share repurchases or making any Permitted Acquisitions (as defined in the Credit Agreement). Additionally, during the Initial Covenant Relief Period, the aggregate amount of all capital expenditures made by the Company could not exceed $7.0 million, and the Company was prohibited from making any earn-out payments if, after giving effect to such earn-out payment, the Company’s liquidity would be less than $5.0 million or the aggregate amount of all earn-out payments made by the Company during the Initial Covenant Relief Period would exceed $7.0 million. Pursuant to the Fourth Amendment, the Initial Covenant Relief Period was extended from July 2, 2021 to and including the earlier of (i) April 1, 2022 and (ii) the last day of the fiscal quarter in which the Company delivers an irrevocable election to terminate the covenant relief granted by the Fourth Amendment (the “Second Covenant Relief Period,” and together with the Initial Covenant Relief Period, the “Amended Covenant Relief Period”). The Fourth Amendment also (A) increased the maximum Leverage Ratio the Company was permitted to maintain to 4.50 to 1.00 through June 30, 2021, 5.25 to 1.00 through September 30, 2021, 4.50 to 1.00 through December 31, 2021, 4.25 to 1.00 through March 31, 2022, and 3.25 to 1.00 through June 30, 2022 and thereafter, (B) established the minimum Adjusted EBITDA thresholds (as defined in the Third Amendment) for the remainder of the Amended Covenant Relief Period, (C) removed the previous prohibition during the Initial Covenant Relief Period on the Company’s ability to make delayed draw term loan borrowings, (D) removed the previous prohibition during the Initial Covenant Relief Period on the Company’s ability to make Permitted Acquisitions (as defined in the Credit Agreement) and to purchase, redeem or otherwise acquire the Company’s common stock, in each case, subject to certain conditions, and (E) increased the maximum amount of earn-out payments the Company was permitted to make during the Amended Covenant Relief Period from $7.0 million to $17.0 million, provided that the Company’s liquidity would not be less than $10.0 million after giving effect to such earn-out payment. Additionally, during the remainder of the Amended Covenant Relief Period, the aggregate amount of all capital expenditures made by the Company may not exceed $15.0 million. ​ In accordance with the Fourth Amendment, borrowings under the Credit Agreement bore interest at all times other than during the Initial Covenant Relief Period, at either a Base Rate or London Inter-Bank Offered Rate (“LIBOR”), each as defined in the Credit Agreement, at the Company’s option, and in each case plus an applicable margin, which applicable margin ranged from 0.125% to 1.25% with respect to Base Rate borrowings and 1.125% to 2.25% with respect to LIBOR borrowings, depending on the Leverage Ratio; provided, that LIBOR could not be less than 0.00%. The Company also agreed to pay a commitment fee for the unused portion of the Revolving Credit Facility and the delayed draft term loan facility, which ranged from 0.15% to 0.40% per annum depending on the Leverage Ratio, and fees on the face amount of any letters of credit outstanding under the Revolving Credit Facility, which ranged from 0.84% to 1.688% per annum, in each case, depending on whether such letter of credit is a performance or financial letter of credit and the Leverage Ratio. ​ The Credit Agreement includes customary events of default and also contains other customary restrictive covenants including (i) restrictions on the incurrence of additional indebtedness and additional liens on property, (ii) restrictions on permitted acquisitions and other investments and (iii) limitations on asset sales, mergers and acquisitions. Further, the Credit Agreement limits the Company’s payment of future dividends and distributions and share repurchases by the Company. Subject to certain exceptions, borrowings under the Credit Agreement are also subject to mandatory prepayment from (a) any issuances of debt or equity securities, (b) any sale or disposition of assets, (c) insurance and condemnation proceeds (d) representation and warranty insurance proceeds related to insurance policies issued in connection with acquisitions and (e) excess cash flow. ​ Fifth Amendment to the Credit Agreement ​ On March 8, 2022, the Company entered into the Fifth Amendment to the Credit Agreement (the “Fifth Amendment”). The Fifth Amendment extended the Amended Covenant Relief Period from March 31, 2022 to and including the earlier of (i) December 30, 2022 and (ii) the last day of the fiscal quarter in which the Company delivers an irrevocable election to terminate the covenant relief granted by the Fifth Amendment (the “Third Covenant Relief Period,” and together with the Amended Covenant Relief Period, the “Extended Covenant Relief Period”). ​ The Fifth Amendment also (A) amended the minimum Adjusted EBITDA (as defined in the Fifth Amendment) thresholds for the remainder of the Extended Covenant Relief Period, (B) increased the maximum Total Leverage Ratio (as defined in the Credit Agreement) the Company is permitted to maintain through the fiscal quarter ending on December 31, 2022, (C) funded to the Company, on the date of closing, the remaining $20.0 million in available funds from the Delayed Draw Term Loan, and (D) amended the pricing structure of borrowings under the Credit Agreement from utilizing as a reference rate the LIBOR to utilizing the Secured Overnight Financing Rate (“SOFR”). Additionally, during the remainder of the Covenant Relief Period, the aggregate amount of all capital expenditures made by the Company may not exceed $20.0 million. Pursuant to the Fifth Amendment, during the Extended Covenant Relief Period, borrowings under the Credit Agreement will bear interest at either a Base Rate or SOFR (plus 0.10% or 0.15% depending on the interest period), each as defined in the Credit Agreement, at the Company’s option, and in each case, plus an applicable margin, which applicable margin will range from 0.125% to 1.50% with respect to Base Rate borrowings and 1.125% to 2.50% with respect to SOFR borrowings, depending on the Leverage Ratio; provided, that SOFR cannot be less than 0.00%. The Company will also pay a commitment fee for the unused portion of the revolving credit facility and the delayed draft term loan facility under the Credit Agreement, which will range from 0.15% to 0.45% per annum depending on the Leverage Ratio, and fees on the face amount of any letters of credit outstanding under the revolving credit facility, which will range from 0.84% to 1.875% per annum, in each case, depending on whether such letter of credit is a performance or financial letter of credit and the Leverage Ratio. ​ After the Extended Covenant Relief Period, borrowings under the Credit Agreement will bear interest at either a Base Rate or SOFR (plus 0.10% or 0.15% depending on the interest period), each as defined in the Credit Agreement, at the Company’s option, and in each case, plus an applicable margin, which applicable margin will range from 0.125% to 1.25% with respect to Base Rate borrowings and 1.125% to 2.25% with respect to SOFR borrowings, depending on the Leverage Ratio; provided, that SOFR cannot be less than 0.00%. The Company will also pay a commitment fee for the unused portion of the revolving credit facility and the delayed draft term loan facility under the Credit Agreement, which will range from 0.15% to 0.40% per annum depending on the Leverage Ratio, and fees on the face amount of any letters of credit outstanding under the revolving credit facility, which will range from 0.84% to 1.688% per annum, in each case, depending on whether such letter of credit is a performance or financial letter of credit and the Leverage Ratio. ​ As of July 1, 2022, the Company was in compliance with all covenants contained in the Credit Agreement, as amended. Other Debt Agreements The Company’s other debt agreements are related to financed insurance premiums, a financed software agreement, and a utility customer agreement and are immaterial to the Company’s Condensed Consolidated Financial Statements. ​ ​

LEASES

LEASES	6 Months Ended
	Jul. 01, 2022
LEASES
LEASES	7. LEASES The Company leases certain office facilities under long-term, non-cancellable operating leases that expire at various dates through the year 2027. In addition, the Company is obligated under finance leases for certain furniture and office equipment that expire at various dates through the year 2026. From time to time, the Company enters into non-cancelable leases for some of its facility and equipment needs. These leases allow the Company to conserve cash by paying a monthly lease rental fee for the use of facilities and equipment rather than purchasing them. The Company’s leases have terms ranging from one to eight years , some of which may include options to extend the leases for up to five years , and some of which may include options to terminate the leases within one year . Currently, all of the Company’s leases contain fixed payment terms. The Company may decide to cancel or terminate a lease before the end of its term, in which case the Company is typically liable to the lessor for the remaining lease payments under the term of the lease. Additionally, all of the Company’s month-to-month leases are cancelable by the Company or the lessor, at any time, and are not included in the Company’s right-of-use asset or lease liability. As of July 1, 2022, the Company had no leases with residual value guarantees. Typically, the Company has purchase options on the equipment underlying its long-term leases. The Company may exercise some of these purchase options when the need for equipment is on-going and the purchase option price is attractive. Nonperformance-related default covenants, cross-default provisions, subjective default provisions and material adverse change clauses contained in material lease agreements, if any, are also evaluated to determine whether those clauses affect lease classification in accordance with “ASC” Topic 842-10-25. Leases are accounted for as operating or financing leases, depending on the terms of the lease. ​ Financing Leases ​ The Company leases certain equipment under financing leases. The economic substance of the leases is a financing transaction for acquisition of equipment and leasehold improvements. Accordingly, the right-of-use assets for these leases are included in the balance sheets in equipment and leasehold improvements, net of accumulated depreciation, with a corresponding amount recorded in current portion of financing lease obligations or noncurrent portion of financing lease obligations, as appropriate. The financing lease assets are amortized over the life of the lease or, if shorter, the life of the leased asset, on a straight-line basis and included in depreciation expense. The interest associated with financing lease obligations is included in interest expense. Right-of-use assets Operating leases are included in right-of-use assets, and current portion of lease liability and noncurrent portion of lease liability, as appropriate. Right-of-use assets and lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at commencement date. As most of the Company’s leases do not provide an implicit rate to calculate present value, the Company determines this rate by estimating the Company’s incremental borrowing rate at the lease commencement date. The right-of-use asset also includes any lease payments made and initial direct costs incurred at lease commencement and excludes lease incentives. The Company’s lease terms may include options to extend or terminate the lease when it is reasonably certain that it will exercise that option. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. ​ ​ The following is a summary of the Company’s lease expense: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ July 1, ​ July 2, ​ July 1, ​ July 2, ​ 2022 2021 2022 2021 ​ (in thousands) ​ (in thousands) Operating lease cost $ 1,534 ​ $ 1,653 ​ $ 3,112 ​ $ 3,345 Finance lease cost: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortization of assets ​ 255 ​ ​ 135 ​ ​ 488 ​ ​ 258 Interest on lease liabilities ​ 15 ​ ​ 7 ​ ​ 29 ​ ​ 13 Total net lease cost $ 1,804 ​ $ 1,795 ​ $ 3,629 ​ $ 3,616 ​ The following is a summary of lease information presented on the Company’s consolidated balance sheet: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ July 1, December 31, ​ ​ ​ 2022 ​ 2021 ​ ​ ​ (in thousands) ​ Operating leases: ​ ​ ​ ​ ​ ​ ​ Right-of-use assets ​ $ 13,387 ​ $ 15,177 ​ ​ ​ ​ ​ ​ ​ Lease liability ​ $ 5,435 ​ $ 5,575 ​ Lease liability, less current portion ​ 8,956 ​ 10,768 ​ Total lease liabilities ​ $ 14,391 ​ $ 16,343 ​ ​ ​ ​ ​ ​ ​ Finance leases (included in equipment and leasehold improvements, net): ​ ​ ​ ​ ​ ​ ​ Equipment and leasehold improvements, net ​ $ 4,541 ​ $ 3,286 ​ Accumulated depreciation ​ (2,259) ​ (1,947) ​ Total equipment and leasehold improvements, net ​ $ 2,282 ​ $ 1,339 ​ ​ ​ ​ ​ ​ ​ ​ Finance lease obligations ​ $ 891 ​ $ 539 ​ Finance lease obligations, less current portion ​ ​ 1,413 ​ ​ 778 ​ Total finance lease obligations ​ $ 2,304 ​ $ 1,317 ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average remaining lease term (in years): ​ ​ ​ ​ ​ ​ ​ Operating Leases ​ ​ 3.55 ​ ​ 3.79 ​ Finance Leases ​ ​ 2.65 ​ ​ 2.62 ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average discount rate: ​ ​ ​ ​ ​ ​ ​ Operating Leases ​ ​ 4.13 % ​ 4.28 % Finance Leases ​ ​ 2.57 % ​ 2.78 % ​ Rent expense was $1.7 million and $3.3 million for the three and six months ended July 1, 2022, respectively, as compared to $1.8 million and $3.6 million for the three and six months ended July 2, 2021, respectively. ​ ​ ​ The following is a summary of other information and supplemental cash flow information related to finance and operating leases: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Six Months Ended ​ ​ July 1, ​ July 2, ​ ​ 2022 2021 ​ ​ (in thousands) Cash paid for amounts included in the measurement of lease liabilities: ​ ​ ​ ​ ​ ​ Operating cash flow from operating leases ​ $ 3,273 ​ $ 3,477 Operating cash flow from finance leases ​ ​ 29 ​ ​ 13 Financing cash flow from finance leases ​ ​ 444 ​ ​ 214 ​ ​ ​ ​ ​ ​ ​ Right-of-use assets obtained in exchange for lease liabilities: ​ ​ ​ ​ ​ ​ Operating leases ​ $ 1,002 ​ $ 240 ​ The following is a summary of the maturities of lease liabilities as of July 1, 2022: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating Finance ​ ​ (in thousands) ​ Fiscal year: ​ ​ ​ ​ ​ ​ ​ Remainder of 2022 ​ $ 3,117 ​ $ 522 ​ 2023 ​ 4,543 ​ 947 ​ 2024 ​ 3,030 ​ ​ 674 ​ 2025 ​ ​ 2,225 ​ ​ 157 ​ 2026 ​ ​ 2,159 ​ 73 ​ 2027 and thereafter ​ 453 ​ 7 ​ Total lease payments ​ ​ 15,527 ​ ​ 2,380 ​ Less: Imputed interest ​ (1,136) ​ ​ (76) ​ Total lease obligations ​ 14,391 ​ ​ 2,304 ​ Less: Current obligations ​ 5,435 ​ ​ 891 ​ Noncurrent lease obligations ​ $ 8,956 ​ $ 1,413 ​ ​ The imputed interest for finance lease obligations represents the interest component of finance leases that will be recognized as interest expense in future periods. The financing component for operating lease obligations represents the effect of discounting the operating lease payments to their present value. ​

COMMITMENTS AND VARIABLE INTERE

COMMITMENTS AND VARIABLE INTEREST ENTITIES	6 Months Ended
	Jul. 01, 2022
COMMITMENTS AND VARIABLE INTEREST ENTITIES
COMMITMENTS AND VARIABLE INTEREST ENTITIES	8. COMMITMENTS AND VARIABLE INTEREST ENTITIES Employee Benefit Plans The Company has a qualified profit sharing plan pursuant to Code Section 401(a) and qualified The Company’s defined contribution plan (the “Plan”) covers employees who have completed three months of service and who have attained 21 years of age. Employees may elect to contribute up to 50% of their compensation limited to the amount allowed by tax laws. The Company elects to make matching contributions equal to 50% of the participants’ contributions to the Plan, up to 6% of the individual participant’s compensation, and subject to a maximum of $3,000 per employee. Under the Plan, the Company’s matching contributions to employee accounts are discretionary. During the six months ended July 1, 2022 and July 2, 2021, the Company made matching contributions of $1.6 million and $1.3 million, respectively. Variable Interest Entities On March 4, 2016, the Company and the Company’s wholly-owned subsidiary, WES, acquired substantially all of the assets of Genesys and assumed certain specified liabilities of Genesys (collectively, the “Purchase”) pursuant to an Asset Purchase and Merger Agreement, dated as of February 26, 2016 (the “Agreement”), by and among Willdan Group, Inc., WES, WESGEN (as defined below), Genesys and Ronald W. Mineo (“Mineo”) and Robert J. Braun (“Braun” and, together with Mineo, the “Genesys Shareholders”). On March 5, 2016, pursuant to the terms of the Agreement, WESGEN, Inc., a non-affiliated corporation (“WESGEN”), merged (the “Merger” and, together with the Purchase, the “Acquisition”) with Genesys, with Genesys remaining as the surviving corporation. Genesys was acquired to strengthen the Company’s power engineering capability in the northeastern U.S., and also to increase client exposure and experience with universities. Genesys continues to be a professional corporation organized under the laws of the State of New York, wholly-owned by one or more licensed engineers. Pursuant to New York law, the Company does not own capital stock of Genesys. The Company has entered into an agreement with the Shareholder of Genesys pursuant to which the Shareholder will be prohibited from selling, transferring or encumbering the Shareholder’s ownership interest in Genesys without the Company’s consent. Notwithstanding the Company’s rights regarding the transfer of Genesys’s stock, the Company does not have control over the professional decision making of Genesys’s engineering services. The Company has entered into an administrative services agreement with Genesys pursuant to which WES will provide Genesys with ongoing administrative, operational and other non-professional support services. Genesys pays WES a service fee, which consists of all of the costs incurred by WES to provide the administrative services to Genesys plus ten percent of such costs, as well as any other costs that relate to professional service supplies and personnel costs. As a result of the administrative services agreement, the Company absorbs the expected losses of Genesys through its deferral of Genesys’s service fees owed to WES. ​

SEGMENT AND GEOGRAPHICAL INFORM

SEGMENT AND GEOGRAPHICAL INFORMATION	6 Months Ended
	Jul. 01, 2022
SEGMENT AND GEOGRAPHICAL INFORMATION
SEGMENT AND GEOGRAPHICAL INFORMATION	9. SEGMENT AND GEOGRAPHICAL INFORMATION Segment Information The Company’s two segments are Energy and Engineering and Consulting, and the Company’s chief operating decision maker, which continues to be its chief executive officer, receives and reviews financial information in this format. There were no intersegment sales during the three and six months ended July 1, 2022 and July 2, 2021. The Company’s chief operating decision maker evaluates the performance of each segment based upon income or loss from operations before income taxes. Certain segment asset information including expenditures for long-lived assets has not been presented as it is not reported to or reviewed by the chief operating decision maker. In addition, enterprise-wide service line contract revenue is not included as it is impracticable to report this information for each group of similar services. Financial information with respect to the reportable segments is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Engineering ​ Unallocated ​ ​ ​ ​ Consolidated ​ Energy & Consulting Corporate Intersegment Total ​ ​ (in thousands) Fiscal Three Months Ended July 1, 2022 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contract revenue ​ $ 84,675 ​ $ 17,970 ​ $ - ​ $ - ​ $ 102,645 Depreciation and amortization ​ ​ 4,183 ​ ​ 243 ​ ​ - ​ ​ - ​ ​ 4,426 Interest expense, net ​ ​ 1 ​ ​ - ​ ​ 1,029 ​ ​ - ​ ​ 1,030 Segment profit (loss) before income tax expense ​ ​ (6,357) ​ ​ 2,531 ​ ​ (2,173) ​ ​ - ​ ​ (5,999) Income tax expense (benefit) ​ ​ (1,891) ​ ​ 732 ​ ​ (514) ​ ​ - ​ ​ (1,673) Net income (loss) ​ ​ (4,467) ​ ​ 1,798 ​ ​ (1,657) ​ ​ - ​ ​ (4,326) Segment assets (1) ​ ​ 323,070 ​ ​ 23,293 ​ ​ 58,650 ​ ​ (23,130) ​ ​ 381,883 Fiscal Three Months Ended July 2, 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contract revenue ​ $ 66,447 ​ $ 17,707 ​ $ - ​ $ - ​ $ 84,154 Depreciation and amortization ​ ​ 3,973 ​ ​ 251 ​ ​ - ​ ​ - ​ ​ 4,224 Interest expense, net ​ ​ 1 ​ ​ - ​ ​ 1,098 ​ ​ - ​ ​ 1,099 Segment profit (loss) before income tax expense ​ ​ (4,913) ​ ​ 2,724 ​ ​ (6,075) ​ ​ - ​ ​ (8,264) Income tax expense (benefit) ​ ​ (2,151) ​ ​ 1,247 ​ ​ (2,759) ​ ​ - ​ ​ (3,663) Net income (loss) ​ ​ (2,762) ​ ​ 1,478 ​ ​ (3,317) ​ ​ - ​ ​ (4,601) Segment assets (1) ​ ​ 322,255 ​ ​ 22,952 ​ ​ 58,410 ​ ​ (23,130) ​ ​ 380,487 Fiscal Six Months Ended July 1, 2022 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contract revenue ​ $ 159,561 ​ $ 34,922 ​ $ - ​ $ - ​ $ 194,483 Depreciation and amortization ​ ​ 8,340 ​ ​ 495 ​ ​ - ​ ​ - ​ ​ 8,835 Interest expense, net ​ ​ 5 ​ ​ - ​ ​ 1,776 ​ ​ - ​ ​ 1,781 Segment profit (loss) before income tax expense ​ ​ (10,710) ​ ​ 4,638 ​ ​ (6,089) ​ ​ - ​ ​ (12,161) Income tax expense (benefit) ​ ​ (3,578) ​ ​ 1,549 ​ ​ (2,033) ​ ​ - ​ ​ (4,062) Net income (loss) ​ ​ (7,132) ​ ​ 3,088 ​ ​ (4,055) ​ ​ - ​ ​ (8,099) Segment assets (1) ​ ​ 323,070 ​ ​ 23,293 ​ ​ 58,650 ​ ​ (23,130) ​ ​ 381,883 Fiscal Six Months Ended July 2, 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contract revenue ​ $ 128,454 ​ $ 34,786 ​ $ - ​ $ - ​ $ 163,240 Depreciation and amortization ​ ​ 7,911 ​ ​ 500 ​ ​ - ​ ​ - ​ ​ 8,411 Interest expense, net ​ ​ 5 ​ ​ - ​ ​ 2,158 ​ ​ - ​ ​ 2,163 Segment profit (loss) before income tax expense ​ ​ (7,745) ​ ​ 4,834 ​ ​ (10,577) ​ ​ - ​ ​ (13,488) Income tax expense (benefit) ​ ​ (2,941) ​ ​ 1,836 ​ ​ (4,016) ​ ​ - ​ ​ (5,121) Net income (loss) ​ ​ (4,804) ​ ​ 2,999 ​ ​ (6,562) ​ ​ - ​ ​ (8,367) Segment assets (1) ​ ​ 322,255 ​ ​ 22,952 ​ ​ 58,410 ​ ​ (23,130) ​ ​ 380,487 (1) Segment assets are presented net of intercompany receivables. ​ The following tables provide information about disaggregated revenue by contract type, client type and geographical region: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended July 1, 2022 ​ Energy Engineering and Consulting Total ​ (in thousands) Contract Type ​ ​ ​ ​ ​ ​ ​ ​ ​ Time-and-materials ​ $ 7,587 ​ $ 13,340 ​ $ 20,927 Unit-based ​ ​ 42,544 ​ ​ 3,755 ​ ​ 46,299 Fixed price ​ ​ 34,545 ​ ​ 874 ​ ​ 35,419 Total (1) ​ $ 84,675 ​ $ 17,970 ​ $ 102,645 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Client Type ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ $ 6,701 ​ $ 1,476 ​ $ 8,177 Government ​ ​ 29,861 ​ ​ 16,338 ​ ​ 46,199 Utilities (2) ​ ​ 48,114 ​ ​ 156 ​ ​ 48,270 Total (1) ​ $ 84,675 ​ $ 17,970 ​ $ 102,645 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Geography (3) ​ ​ ​ ​ ​ ​ ​ ​ ​ Domestic ​ $ 84,675 ​ $ 17,970 ​ $ 102,645 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Six months ended July 1, 2022 ​ Energy Engineering and Consulting Total ​ (in thousands) Contract Type ​ ​ ​ ​ ​ ​ ​ ​ ​ Time-and-materials ​ $ 16,405 ​ $ 26,341 ​ $ 42,746 Unit-based ​ ​ 85,501 ​ ​ 6,739 ​ ​ 92,240 Fixed price ​ ​ 57,655 ​ ​ 1,842 ​ ​ 59,497 Total (1) ​ $ 159,561 ​ $ 34,922 ​ $ 194,483 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Client Type ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ $ 14,790 ​ $ 2,954 ​ $ 17,744 Government ​ ​ 48,220 ​ ​ 31,791 ​ ​ 80,011 Utilities (2) ​ ​ 96,551 ​ ​ 177 ​ ​ 96,728 Total (1) ​ $ 159,561 ​ $ 34,922 ​ $ 194,483 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Geography (3) ​ ​ ​ ​ ​ ​ ​ ​ ​ Domestic ​ $ 159,561 ​ $ 34,922 ​ $ 194,483 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended July 2, 2021 ​ Energy Engineering and Consulting Total ​ (in thousands) Contract Type ​ ​ ​ ​ ​ ​ ​ ​ ​ Time-and-materials ​ $ 9,056 ​ $ 13,863 ​ $ 22,919 Unit-based ​ ​ 41,604 ​ ​ 2,722 ​ ​ 44,326 Fixed price ​ ​ 15,786 ​ ​ 1,123 ​ ​ 16,909 Total (1) ​ $ 66,446 ​ $ 17,708 ​ $ 84,154 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Client Type ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ $ 7,016 ​ $ 1,372 ​ $ 8,388 Government ​ ​ 13,675 ​ ​ 16,281 ​ ​ 29,956 Utilities (2) ​ ​ 45,756 ​ ​ 55 ​ ​ 45,811 Total (1) ​ $ 66,446 ​ $ 17,708 ​ $ 84,154 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Geography (3) ​ ​ ​ ​ ​ ​ ​ ​ ​ Domestic ​ $ 66,446 ​ $ 17,708 ​ $ 84,154 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Six months ended July 2, 2021 ​ Energy Engineering and Consulting Total ​ (in thousands) Contract Type ​ ​ ​ ​ ​ ​ ​ ​ ​ Time-and-materials ​ $ 15,956 ​ $ 27,284 ​ $ 43,240 Unit-based ​ ​ 81,218 ​ ​ 5,167 ​ ​ 86,385 Fixed price ​ ​ 31,279 ​ ​ 2,336 ​ ​ 33,615 Total (1) ​ $ 128,453 ​ $ 34,787 ​ $ 163,240 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Client Type ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ $ 12,944 ​ $ 2,469 ​ $ 15,413 Government ​ ​ 27,229 ​ ​ 32,210 ​ ​ 59,439 Utilities (2) ​ ​ 88,280 ​ ​ 108 ​ ​ 88,388 Total (1) ​ $ 128,453 ​ $ 34,787 ​ $ 163,240 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Geography (3) ​ ​ ​ ​ ​ ​ ​ ​ ​ Domestic ​ $ 128,453 ​ $ 34,787 ​ $ 163,240 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) Amounts may not add to the totals due to rounding. (2) Includes the portion of revenue related to small business programs paid by the end user/customer. (3) Revenue from the Company’s foreign operations were not material for the three and six months ended July 1, 2022 and July 2, 2021. ​ Geographical Information ​ Substantially all of the Company’s consolidated revenue was derived from its operations in the U.S. The Company operates through a network of offices spread across 23 U.S. states, the District of Columbia, and Canada. Revenues from the Company’s Canadian operations were not material for the three and six months ended July 1, 2022 nor the three and six months ended July 1, 2021. Customer Concentration For the three and six months ended July 1, 2022, the Company’s top 10 customers accounted for 55.4%, and 54.4%, respectively, of the Company’s consolidated contract revenue. For the three and six months ended July 2, 2021, the Company’s top 10 customers accounted for 48.4%, and 46.2%, respectively, of the Company’s consolidated contract revenue. For the three and six months ended July 1, 2022, the Company had one customer, LADWP, that accounted for 14.6% and 15.8%, respectively, of its consolidated contract revenues . On a segment basis, the Company had individual customers that accounted for more than 10% of its segment contract revenues. For the three and six months ended July 1, 2022, the Company derived 17.6% and 19.2%, respectively, of its Energy segment revenues from one customer, LADWP. For the three and six months ended July 1, 2022, no single customer accounted for 10% or more of . For the three and six months ended July 1, 2021, the Company derived 11.5% and 10.9% , respectively, of its Energy segment revenues from one customer, Consolidated Edison of New York, and it derived 13.9% and 15.8% , respectively, of its Engineering and Consulting segment revenues from one customer, the City of Elk Grove. The Company’s largest clients are based in California and New York. For the three and six months ended July 1, 2022, services provided to clients in California accounted for 40.9% and 42.2%, respectively, of the Company’s contract revenue and services provided to clients in New York accounted for 19.6% and 20.2%, respectively, of the Company’s contract revenue. For the three and six months ended July 2, 2021, services provided to clients in California accounted for 34.8% and 34.5%, respectively, of the Company’s contract revenue and services provided to clients in New York accounted for 21.6% and 21.8%, respectively, of the Company’s contract revenue.

INCOME TAXES

INCOME TAXES	6 Months Ended
	Jul. 01, 2022
INCOME TAXES
INCOME TAXES	10. INCOME TAXES Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences of temporary differences between the financial reporting basis and tax basis of the Company’s assets and liabilities, subject to a judgmental assessment of the recoverability of deferred tax assets. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. A valuation allowance is recorded when it is more likely than not that some of the deferred tax assets may not be realized. Significant judgment is applied when assessing the need for valuation allowances and includes the evaluation of historical income (loss) adjusted for the effects of non-recurring items and the impact of recent business combinations. Areas of estimation include our consideration of future taxable income which is driven by verifiable signed contracts and ongoing prudent and feasible tax planning strategies. Should a change in circumstances lead to a change in judgment about the utilization of deferred tax assets in future years, the Company would adjust the related valuation allowances in the period that the change in circumstances occurs, along with a corresponding increase or charge to income. During each fiscal year, the Company assesses the available positive and negative evidence to evaluate if it is more likely than not that the deferred tax assets will be realized. At the end of fiscal year 2018, the Company determined that it was more-likely-than-not that the entire California net operating loss will not be utilized prior to expiration. Significant pieces of objective evidence evaluated included the Company’s history of utilization of California net operating losses in prior years for each of its subsidiaries, as well as its forecasted amount of net operating loss utilization for certain members of the combined group. As a result, at that time, the Company recorded a valuation allowance in the amount of $86,000 related to California net operating losses. During fiscal year 2021, the Company determined that it was more-likely-than-not that the New Jersey net operating losses will not be utilized prior to expiration and, accordingly, recorded a valuation allowance of $1.1 million. Significant pieces of objective evidence evaluated included the Company’s proportional increase of revenue to other states resulting in a dilution of New Jersey sourced income as well as the Company’s forecasted amount of net operating loss utilization in New Jersey for certain members of the combined group. At the end of fiscal year 2021, the total valuation allowance was $1.2 million, compared to a balance of $86,000 for fiscal year 2020. As of July 1, 2022, the Company assessed all available positive and negative evidence available to determine whether, based on the weight of that evidence, there was a change in judgment related to the utilization of deferred tax assets in future years. The Company concluded that as of July 1, 2022, the valuation allowance for the Company’s deferred tax assets was appropriate in accordance with ASC 740. Consequently, there was no change to the valuation allowance during the three and six months ended July 1, 2022. For acquired business entities, if the Company identifies changes to acquired deferred tax asset valuation allowances or liabilities related to uncertain tax positions during the measurement period and they relate to new information obtained about facts and circumstances that existed as of the acquisition date, those changes are considered a measurement period adjustment, and the Company records the offset to goodwill. The Company records all other changes to deferred tax asset valuation allowances and liabilities related to uncertain tax positions in current period income tax expense. The Company recognizes the tax benefit from uncertain tax positions if it is more likely than not that the tax positions will be sustained on examination by the tax authorities, based on the technical merits of the position. The tax benefit is measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement. The Company recognizes interest and penalties related to unrecognized tax benefits in income tax expense. During the three and six months ended July 1, 2022, the Company did not record a liability for uncertain tax positions. Based on the Company’s estimates and determination of an effective tax rate for the year, the Company recorded an income tax benefit of $1.7 million and $4.1 million for the three and six months ended July 1, 2022, respectively, as compared to an income tax benefit of $3.7 million and $5.1 million for the three and six months ended July 2, 2021, respectively. During the three and six months ended July 1, 2022, the difference between the effective tax rate and the federal statutory rate was primarily attributable to state taxes, non-deductible stock compensation, nondeductible executive compensation, research and development tax credits, and the commercial building energy efficiency deduction. During the three and six months ended July 2, 2021, the difference between the effective tax rate and the federal statutory rate was primarily attributable to state taxes, excess tax benefit on stock compensation, nondeductible executive compensation, research and development tax credits, the commercial building energy efficiency deduction, and additional benefits provided by the Coronavirus Aid, Relief, and Economic Security (CARES) Act (H.R 748). On June 10, 2021, the Company received notice from the State of New York indicating that the Company’s 2017 , 2018 , and 2019 state tax returns were under examination. The examination was finalized during the Company’s first quarter of fiscal 2022 and there were no changes made by the State of New York to the state tax returns filed. ​

EARNINGS PER SHARE (EPS)

EARNINGS PER SHARE (EPS)	6 Months Ended
	Jul. 01, 2022
EARNINGS PER SHARE (EPS)
EARNINGS PER SHARE (EPS)	11. EARNINGS PER SHARE (“EPS”) Basic EPS is computed by dividing net income available to common stockholders by the weighted-average number of common shares outstanding. Diluted EPS is computed by dividing net income by the weighted-average number of common shares outstanding and dilutive potential common shares for the period. Potential common shares include the weighted-average dilutive effects of outstanding stock options and restricted stock awards using the treasury stock method. The following table sets forth the number of weighted-average common shares outstanding used to compute basic and diluted EPS: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended ​ Six months ended ​ ​ July 1, ​ July 2, ​ July 1, ​ July 2, ​ 2022 2021 2022 2021 ​ ​ (in thousands, except per share amounts) Net income (loss) ​ $ (4,326) ​ $ (4,601) ​ $ (8,099) ​ $ (8,367) Weighted-average common shares outstanding ​ 13,016 ​ 12,421 ​ 12,901 ​ 12,284 Effect of dilutive stock options and restricted stock awards ​ — ​ — ​ — ​ — Weighted-average common shares outstanding-diluted ​ 13,016 ​ 12,421 ​ 12,901 ​ 12,284 Earnings (Loss) per share: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic ​ $ (0.33) ​ $ (0.37) ​ $ (0.63) ​ $ (0.68) Diluted ​ $ (0.33) ​ $ (0.37) ​ $ (0.63) ​ $ (0.68) ​ For the three and six months ended July 1, 2022 and July 2, 2021, the Company reported a net loss, and accordingly, all outstanding equity awards have been excluded from such periods because including them would have been anti-dilutive. ​

CONTINGENCIES

CONTINGENCIES	6 Months Ended
	Jul. 01, 2022
CONTINGENCIES
CONTINGENCIES	12. CONTINGENCIES Claims and Lawsuits The Company is subject to claims and lawsuits from time to time, including those alleging professional errors or omissions that arise in the ordinary course of business against firms that operate in the engineering and consulting professions. The Company carries professional liability insurance, subject to certain deductibles and policy limits, for such claims as they arise and may from time to time establish reserves for litigation that is considered probable of a loss. In accordance with accounting standards regarding loss contingencies, the Company accrues an undiscounted liability for those contingencies where the incurrence of a loss is probable and the amount can be reasonably estimated, and discloses the amount accrued and an estimate of any reasonably possible loss in excess of the amount accrued, if such disclosure is necessary for the Company’s financial statements not to be misleading. The Company does not accrue liabilities when the likelihood that the liability has been incurred is probable but the amount cannot be reasonably estimated, or when the liability is believed to be only reasonably possible or remote. Because litigation outcomes are inherently unpredictable, the Company’s evaluation of legal proceedings often involves a series of complex assessments by management about future events and can rely heavily on estimates and assumptions. If the assessments indicate that loss contingencies that could be material to any one of the Company’s financial statements are not probable, but are reasonably possible, or are probable, but cannot be estimated, then the Company will disclose the nature of the loss contingencies, together with an estimate of the possible loss or a statement that such loss is not reasonably estimable. While the consequences of certain unresolved proceedings are not presently determinable, and a reasonable estimate of the probable and reasonably possible loss or range of loss in excess of amounts accrued for such proceedings cannot be made, an adverse outcome from such proceedings could have a material adverse effect on the Company’s earnings in any given reporting period. However, in the opinion of the Company’s management, after consulting with legal counsel, and taking into account insurance coverage, the ultimate liability related to current outstanding claims and lawsuits is not expected to have a material adverse effect on the Company’s financial statements. ​

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	6 Months Ended
	Jul. 01, 2022
SUBSEQUENT EVENTS
SUBSEQUENT EVENTS	13. SUBSEQUENT EVENTS ​ Sixth Amendment to the Credit Agreement ​ On August 2, 2022, the Company entered into the Sixth Amendment to the Credit Agreement (the “Sixth Amendment”). T he Sixth Amendment increased the purchase money indebtedness and Capitalized Lease Obligations (as defined in the Credit Agreement) permissible limit from $1.5 million to $4.0 million. ​ ​ ​ ​ ​ ​ ​

ORGANIZATION AND OPERATIONS O_2

ORGANIZATION AND OPERATIONS OF THE COMPANY (Policies)	6 Months Ended
	Jul. 01, 2022
ORGANIZATION AND OPERATIONS OF THE COMPANY
Basis of Presentation	The accounting policies followed by the Company are set forth in Part II, Item 8, Note 1, Organization and Operations of the Company
Fiscal Years	Fiscal Years The Company operates and reports its annual financial results based on 52 or 53-week periods ending on the Friday closest to December 31. The Company operates and reports its quarterly financial results based on the 13-week period ending on the Friday closest to June 30, September 30, and December 31 and the 13 or 14-week period ending on the Friday closest to March 31, as applicable. Fiscal year 2022, which ends on December 30, 2022, will be comprised of 52 weeks, with all quarters consisting of 13 weeks each. Fiscal year 2021, which ended on December 31, 2021, was comprised of 52 weeks, with all quarters consisting of 13 weeks each. All references to years in the notes to consolidated financial statements represent fiscal years.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements. Estimates also affect the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates.
Historical and Current Impact of Covid-19	Historical and Current Impact of Covid-19 The coronavirus (“Covid-19”) pandemic and efforts to limit its spread negatively impacted the Company’s operations during its fiscal year 2020 and continued to impact the Company, albeit to a lesser extent, during fiscal year 2021. In California and New York, the states in which the Company has historically derived a majority of its revenue, mandatory shutdown orders were issued in March 2020 followed by phased re-openings that began in May 2020, followed by periods of curtailments as a result of resurgences of Covid-19 cases, and subsequent re-openings through 2020 and 2021. The Company’s largest program for the Los Angeles Department of Water and Power (“LADWP”) resumed in the third quarter of fiscal 2021 and was the Company’s last program suspended due to Covid-19. In addition, through fiscal year 2020 and 2021, none of the Company’s contracts were cancelled due to Covid-19. ​ ​ Asset and liability valuation and other estimates used in preparation of financial statements not long-lived assets Impact on Clients and Subcontractors and Other Risks The Company primarily works for utilities, municipalities and other public agencies. Should there be a resurgence related to Covid-19, some of these customers could experience significant budget shortfalls for the current year and beyond as a result of the measures taken to mitigate the resurgence effects of the Covid-19 pandemic and/or revenue shortfalls as a result of reduced economic activity. Although none of the Company’s contracts with governmental or public agencies were materially modified during its fiscal year 2020 or fiscal year 2021, these potential budget deficits could result in delayed funding for existing contracts with the Company, postponements of new contracts or price concessions. Further, most of the Company’s clients are not committed to purchase any minimum amount of services, as the Company agreements with them are based on a “purchase order” or “master service agreement” model. As a result, they may discontinue utilizing some or all of the Company’s services with little or no notice. In addition, the Company relies on subcontractors and material suppliers to complete a substantial portion of its work, especially in its Energy segment. If the Company’s significant subcontractors and material suppliers suffer significant economic harm and must limit or cease operations or file for bankruptcy as a result of the current economic slowdown, the Company’s subcontractors and material suppliers may not be able to fulfill their contractual obligations satisfactorily and the Company may not have the ability to select its subcontractors and material suppliers of choice for new contracts. If the Company’s subcontractors and material suppliers are not able to fulfill their contractual obligations, it could result in a significant increase in costs for the Company to complete the projects or cause significant delays to the realization of revenues under those projects. The ultimate impact of Covid-19 on the Company’s financial condition and results of operations will depend on all of the factors noted above, including other factors that the Company may not be able to forecast at this time. See the risk factor “ The Covid-19 pandemic and health and safety measures intended to slow its spread have adversely affected, and may continue to adversely affect, our business, results of operations and financial condition.

RECENT ACCOUNTING PRONOUNCEME_2

RECENT ACCOUNTING PRONOUNCEMENTS (Policies)	6 Months Ended
	Jul. 01, 2022
RECENT ACCOUNTING PRONOUNCEMENTS
Accounting Pronouncements Recently Adopted and Recently Issued	Accounting Pronouncements Recently Adopted In March 2020, the FASB issued ASU No. 2020-04, “Reference Rate Reform (Topic 848): facilitation of the Effects of Reference Rate Reform on Financial Reporting” (“ASU 2020-04”). ASU 2020-04 provides optional expedients and exceptions for applying U.S. GAAP to contract modifications and hedging relationships that reference LIBOR or another reference rate expected to be discontinued because of reference rate reform. ASU 2020-04 provides, among other things, guidance that modifications of contracts within the scope of Topic 470, Debt, should be accounted for by prospectively adjusting the effective interest rate; modifications of contracts within the scope of Topic 840, Leases, should be accounted for as a continuation of the existing contract; and, changes in the critical terms of hedging relationships, caused by reference rate reform, should not result in the de-designation of the instrument, provided certain criteria are met. In January 2021, the FASB issued ASU No. 2021-01, “Reference Rate Reform (Topic 848) - Scope” (“ASU 2021-01”). ASU 2021-01 clarifies the scope and application of ASU 2020-04 and permits entities, among other things, to elect certain optional expedients and exceptions when accounting for derivative contracts and certain hedging relationships affected by changes in the interest rates used for discounting cash flows. The Company adopted this standard effective March 8, 2022 . The Company’s previous exposure to LIBOR rates included its credit facilities and swap agreement. The adoption of this standard did not have a material impact to the Company’s Condensed Consolidated Financial Statements.

REVENUES (Policies)

REVENUES (Policies)	6 Months Ended
	Jul. 01, 2022
Revenues [Abstract]
Revenue Recognition	The Company enters into contracts with its clients that contain various types of pricing provisions, including fixed price, time-and-materials, and unit-based provisions. The Company recognizes revenues in accordance with ASU 2014-09, Revenue from Contracts with Customer, codified as ASC Topic 606 and the related amendments (collectively “ASC 606”). As such, the Company identifies a contract with a customer, identifies the performance obligations in the contract, determines the transaction price, allocates the transaction price to each performance obligation in the contract and recognizes revenues when (or as) the Company satisfies a performance obligation. The following table reflects the Company’s two reportable segments and the types of contracts that each most commonly enters into for revenue generating activities. ​ Segment Contract Type Revenue Recognition Method ​ Time-and-materials Time-and-materials Energy Unit-based Unit-based ​ Software license Unit-based ​ Fixed price Percentage-of-completion ​ Time-and-materials Time-and-materials Engineering and Consulting Unit-based Unit-based ​ Fixed price Percentage-of-completion ​ Revenue on the vast majority of the Company’s contracts is recognized over time because of the continuous transfer of control to the customer. Revenue on fixed price contracts is recognized on the percentage-of-completion method based generally on the ratio of direct costs incurred-to-date to estimated total direct costs at completion. The Company uses the percentage-of-completion method to better match the level of work performed at a certain point in time in relation to the effort that will be required to complete a project. In addition, the percentage-of-completion method is a common method of revenue recognition in the Company’s industry. Many of the Company’s fixed price contracts involve a high degree of subcontracted fixed price effort and are relatively short in duration, thereby lowering the risks of not properly estimating the percent complete. Revenue on time-and-materials and unit-based contracts is recognized as the work is performed in accordance with the specific rates and terms of the contract. The Company recognizes revenues for time-and-materials contracts based upon the actual hours incurred during a reporting period at contractually agreed upon rates per hour and also includes in revenue all reimbursable costs incurred during a reporting period. Certain of the Company’s time-and-materials contracts are subject to maximum contract values and, accordingly, when revenue is expected to exceed the maximum contract value, these contracts are generally recognized under the percentage-of-completion method, consistent with fixed price contracts. For unit-based contracts, the Company recognizes the contract price of units of a basic production product as revenue when the production product is delivered during a period. Revenue for amounts that have been billed but not earned is deferred, and such deferred revenue is referred to as contract liabilities in the accompanying condensed consolidated balance sheets. The Company also derives revenue from software licenses and professional services and maintenance fees. In accordance with ASC 606, the Company performs an assessment of each contract to identify the performance obligations, determine the overall transaction price for the contract, allocate the transaction price to the performance obligations, and recognize the revenue when the performance obligations are satisfied. The Company utilizes the residual approach by which it estimates the standalone selling price by reference to the total transaction price less the sum of the observable standalone selling prices of other goods or services promised in the contract. The software license revenue is typically recognized at a point in time when control is transferred to the client, which is defined as the point in time when the client can use and benefit from the license. The software license is delivered before related services are provided and is functional without services, updates, or technical support. Related professional services include training and support services in which the standalone selling price is determined based on an input measure of hours incurred to total estimated hours and is recognized over time, usually which is the life of the contract. To determine the proper revenue recognition method for contracts, the Company evaluates whether two or more contracts should be combined and accounted for as one single contract and whether the combined contract should be accounted for as one performance obligation. With respect to the Company’s contracts, it is rare that multiple contracts should be combined into a single performance obligation. This evaluation requires significant judgment and the decision to combine a group of contracts or separate a single contract into multiple performance obligations could change the amount of revenue and profit recorded in a given period. Contracts are considered to have a single performance obligation if the promise to transfer the individual goods or services is not separately identifiable from other promises in the contracts, which is mainly because the Company provides a significant service of integrating a complex set of tasks and components into a single project or capability. The Company may enter into contracts that include separate phases or elements. If each phase or element is negotiated separately based on the technical resources required and/or the supply and demand for the services being provided, the Company evaluates if the contracts should be segmented. If certain criteria are met, the contracts would be segmented which could result in revenues being assigned to the different elements or phases with different rates of profitability based on the relative value of each element or phase to the estimated total contract revenue. Segmented contracts may comprise up to approximately Contracts that cover multiple phases or elements of the project or service lifecycle (development, construction and maintenance and support) may be considered to have multiple performance obligations even when they are part of a single contract. For contracts with multiple performance obligations, the Company allocates the transaction price to each performance obligation using the best estimate of the standalone selling price of each distinct good or service in the contract. For the periods presented, the value of the separate performance obligations under contracts with multiple performance obligations (generally measurement and verification tasks under certain energy performance contracts) were not material. In cases where the Company does not provide the distinct good or service on a standalone basis, the primary method used to estimate standalone selling price is the expected cost plus a margin approach, under which the Company forecasts the Company’s expected costs of satisfying a performance obligation and then adds an appropriate margin for the distinct good or service. The Company provides quality of workmanship warranties to customers that are included in the sale and are not priced or sold separately or do not provide customers with a service in addition to assurance of compliance with agreed-upon specifications and industry standards. The Company does not consider these types of warranties to be separate performance obligations. In some cases, the Company has a master service or blanket agreement with a customer under which each task order releases the Company to perform specific portions of the overall scope in the service contract. Each task order is typically accounted for as a separate contract because the task order establishes the enforceable rights and obligations, and payment terms. Under ASC 606, variable consideration should be considered when determining the transaction price and estimates should be made for the variable consideration component of the transaction price, as well as assessing whether an estimate of variable consideration is constrained. For certain of the Company’s contracts, variable consideration can arise from modifications to the scope of services resulting from unapproved change orders or customer claims. Variable consideration is included in the transaction price to the extent it is probable that a significant reversal of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is resolved. The Company estimates of variable consideration and determination of whether to include estimated amounts in the transaction price are based largely on assessments of legal enforceability, the Company’s performance, and all information (historical, current and forecasted) that is reasonably available to the Company. Due to the nature of the work required to be performed on many of the Company’s performance obligations, the estimation of total revenue and cost at completion is complex, subject to many variables and requires significant judgment. As a significant change in one or more of these estimates could affect the profitability of the Company’s contracts, the Company reviews and updates the Company’s contract-related estimates regularly through a company-wide disciplined project review process in which management reviews the progress and execution of the Company’s performance obligations and the estimate at completion (“EAC”). As part of this process, management reviews information including, but not limited to, any outstanding key contract matters, progress towards completion and the related program schedule and the related changes in estimates of revenues and costs. Management must make assumptions and estimates regarding labor productivity and availability, the complexity of the work to be performed, the cost and availability of materials, the performance of subcontractors, and the availability and timing of funding from the customer, among other variables. The Company recognizes adjustments in estimated profit on contracts under the cumulative catch-up method. Under this method, the impact of the adjustment on profit recorded to date is recognized in the period the adjustment is identified. Revenue and profit in future periods of contract performance is recognized using the adjusted estimate. If at any time the estimate of contract profitability indicates an anticipated loss on the contract, the Company recognizes the full amount of estimated loss in the period it is identified. Contracts are often modified to account for changes in contract specifications and requirements. The Company considers contract modifications to exist when the modification either creates new rights or obligations or changes the existing enforceable rights or obligations. Most of the Company’s contract modifications are for goods or services that are not distinct from existing contracts due to the significant integration provided in the context of the contract and are accounted for as if they were part of the original contract. The effect of a contract modification that is not distinct from the existing contract on the transaction price and the Company’s measure of progress for the performance obligation to which it relates is recognized as an adjustment to revenue (either as an increase in or a reduction of revenue) on a cumulative catch-up basis. For contract modifications that result in the promise to deliver goods or services that are distinct from the existing contract and the increase in price of the contract is for the same amount as the standalone selling price of the additional goods or services included in the modification, the Company accounts for such contract modifications as a separate contract. The Company includes claims to vendors, subcontractors and others as a receivable and a reduction in recognized costs when enforceability of the claim is established by the contract and the amounts are reasonably estimable and probable of being recovered. The amounts are recorded up to the extent of the lesser of the amounts management expects to recover or to costs incurred. Billing practices are governed by the contract terms of each project based upon costs incurred, achievement of milestones or pre-agreed schedules. Billings do not necessarily correlate with revenue recognized using the percentage-of-completion method of revenue recognition. Direct costs of contract revenue consist primarily of that portion of technical and nontechnical salaries and wages that has been incurred in connection with revenue producing projects. Direct costs of contract revenue also include production expenses, subcontractor services and other expenses that are incurred in connection with revenue producing projects. Direct costs of contract revenue exclude that portion of technical and nontechnical salaries and wages related to marketing efforts, vacations, holidays and other time not spent directly generating revenue under existing contracts. Such costs are included in general and administrative expenses. Additionally, payroll taxes, bonuses and employee benefit costs for all Company personnel are included in general and administrative expenses in the accompanying consolidated statements of comprehensive income since no allocation of these costs is made to direct costs of contract revenue. No allocation of facilities costs is made to direct costs of contract revenue. Other companies may classify as direct costs of contract revenue some of the costs that the Company classifies as general and administrative costs. The Company expenses direct costs of contract revenue when incurred. Included in revenue and costs are all reimbursable costs for which the Company has the risk or on which the fee was based at the time of bid or negotiation. No revenue or cost is recorded for costs in which the Company acts solely in the capacity of an agent and has no risks associated with such costs. Accounts receivable are carried at original invoice amount less an estimate made for doubtful accounts based upon a review of all outstanding amounts on a quarterly basis. Management determines allowances for doubtful accounts through specific identification of amounts considered to be uncollectible and potential write-offs, plus a non-specific allowance for other amounts for which some potential loss has been determined to be probable based on current and past experience. The Company’s historical credit losses have been minimal with governmental entities and large public utilities, but disputes may arise related to these receivable amounts. Accounts receivable are written off when deemed uncollectible. Recoveries of accounts receivable previously written off are recorded when received. Retainage, included in contract assets, represents amounts withheld from billings to the Company’s clients pursuant to provisions in the contracts and may not be paid to the Company until specific tasks are completed or the project is completed and, in some instances, for even longer periods. As of July 1, 2022 and December 31, 2021, contract assets included retainage of approximately $6.4 million and $4.5 million, respectively.

REVENUES (Tables)

REVENUES (Tables)	6 Months Ended
	Jul. 01, 2022
REVENUES
Schedule of Contracts by Reportable Segments and Type of Contracts	​ Segment Contract Type Revenue Recognition Method ​ Time-and-materials Time-and-materials Energy Unit-based Unit-based ​ Software license Unit-based ​ Fixed price Percentage-of-completion ​ Time-and-materials Time-and-materials Engineering and Consulting Unit-based Unit-based ​ Fixed price Percentage-of-completion

SUPPLEMENTAL FINANCIAL STATEM_2

SUPPLEMENTAL FINANCIAL STATEMENT DATA (Tables)	6 Months Ended
	Jul. 01, 2022
SUPPLEMENTAL FINANCIAL STATEMENT DATA
Schedule of equipment and leasehold improvements	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ July 1, ​ December 31, ​ 2022 2021 ​ ​ (in thousands) Furniture and fixtures ​ $ 4,018 ​ $ 4,070 Computer hardware and software ​ 30,659 ​ 26,425 Leasehold improvements ​ 3,011 ​ 3,011 Equipment under finance leases ​ 4,541 ​ 3,286 Automobiles, trucks, and field equipment ​ 3,111 ​ 3,099 Subtotal ​ 45,340 ​ 39,891 Accumulated depreciation and amortization ​ (25,958) ​ (23,134) Equipment and leasehold improvements, net ​ $ 19,382 ​ $ 16,757
Schedule of accrued liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ July 1, ​ December 31, ​ 2022 2021 ​ ​ (in thousands) Accrued subcontractor costs ​ $ 22,938 ​ $ 19,727 Other ​ 4,263 ​ 2,750 Employee withholdings ​ 2,943 ​ 2,665 Compensation and payroll taxes ​ 2,546 ​ 2,244 Accrued bonuses ​ ​ 1,733 ​ ​ 7,767 Accrued workers’ compensation insurance ​ 571 ​ 527 Total accrued liabilities ​ $ 34,994 ​ $ 35,680
Schedule of changes in the carrying value of goodwill by reporting unit	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ Additional ​ Additions / ​ July 1, ​ 2021 Purchase Cost Adjustments 2022 ​ ​ (in thousands) Reporting Unit: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Energy ​ $ 129,375 ​ $ — ​ $ — ​ $ 129,375 Engineering and Consulting ​ ​ 749 ​ ​ — ​ ​ — ​ ​ 749 ​ ​ $ 130,124 ​ $ — ​ $ — ​ $ 130,124
Schedule of gross amounts and accumulated amortization of the Company's acquired identifiable intangible assets with finite useful lives	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ July 1, 2022 ​ December 31, 2021 ​ ​ ​ ​ ​ ​ ​ ​ Gross ​ Accumulated ​ Gross ​ Accumulated ​ Amortization ​ Amount Amortization Amount Amortization Period ​ ​ (in thousands) ​ (in years) Finite: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Backlog ​ $ 7,944 ​ $ 7,655 ​ $ 7,944 ​ $ 7,222 ​ 1.0 Tradename ​ 15,911 ​ 9,993 ​ 15,911 ​ 8,997 2.5 ​ - ​ 6.0 Non-compete agreements ​ ​ 1,420 ​ ​ 1,420 ​ ​ 1,420 ​ ​ 1,413 ​ 4.0 ​ - ​ 5.0 Developed technology ​ ​ 15,810 ​ ​ 10,411 ​ ​ 15,500 ​ ​ 8,950 ​ 8.0 Customer relationships ​ ​ 58,149 ​ ​ 22,731 ​ ​ 58,149 ​ ​ 19,939 ​ 5.0 ​ - ​ 8.0 Total finite intangible assets ​ ​ 99,234 ​ ​ 52,210 ​ ​ 98,924 ​ ​ 46,521 ​ ​ ​ ​ ​ ​ In-process research and technology (1) ​ ​ — ​ ​ — ​ ​ 310 ​ ​ — ​ ​ ​ ​ ​ ​ Total intangible assets ​ $ 99,234 ​ $ 52,210 ​ $ 99,234 ​ $ 46,521 ​ ​ ​ ​ ​ ​ (1) In-process research and technology will not be amortized until put into use. ​ During the six months ended July 1, 2022, the Company reclassified $0.3 million of in-process research and technology to developed technology ​

DEBT OBLIGATIONS (Tables)

DEBT OBLIGATIONS (Tables)	6 Months Ended
	Jul. 01, 2022
DEBT OBLIGATIONS
Schedule of debt obligations, excluding obligations under capital leases	​ ​ ​ ​ ​ ​ ​ ​ ​ July 1, December 31, ​ ​ 2022 ​ 2021 ​ ​ (in thousands) Outstanding borrowings on Term A Loan ​ $ 70,000 ​ $ 75,000 Outstanding borrowings on Revolving Credit Facility ​ ​ — ​ ​ — Outstanding borrowings on Delayed Draw Term Loan ​ ​ 42,500 ​ ​ 24,000 Other debt agreements ​ ​ 1,110 ​ ​ 2,161 Total debt ​ ​ 113,610 ​ ​ 101,161 Issuance costs and debt discounts ​ ​ (470) ​ ​ (587) Subtotal ​ ​ 113,140 ​ ​ 100,574 Less current portion of long-term debt ​ 16,019 ​ 15,036 Long-term debt portion ​ $ 97,121 ​ $ 85,538

LEASES (Tables)

LEASES (Tables)	6 Months Ended
	Jul. 01, 2022
LEASES
Summary of the Lease Expense	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ July 1, ​ July 2, ​ July 1, ​ July 2, ​ 2022 2021 2022 2021 ​ (in thousands) ​ (in thousands) Operating lease cost $ 1,534 ​ $ 1,653 ​ $ 3,112 ​ $ 3,345 Finance lease cost: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortization of assets ​ 255 ​ ​ 135 ​ ​ 488 ​ ​ 258 Interest on lease liabilities ​ 15 ​ ​ 7 ​ ​ 29 ​ ​ 13 Total net lease cost $ 1,804 ​ $ 1,795 ​ $ 3,629 ​ $ 3,616
Summary of Lease Information Presented on the Condensed Consolidated Balance Sheet	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ July 1, December 31, ​ ​ ​ 2022 ​ 2021 ​ ​ ​ (in thousands) ​ Operating leases: ​ ​ ​ ​ ​ ​ ​ Right-of-use assets ​ $ 13,387 ​ $ 15,177 ​ ​ ​ ​ ​ ​ ​ Lease liability ​ $ 5,435 ​ $ 5,575 ​ Lease liability, less current portion ​ 8,956 ​ 10,768 ​ Total lease liabilities ​ $ 14,391 ​ $ 16,343 ​ ​ ​ ​ ​ ​ ​ Finance leases (included in equipment and leasehold improvements, net): ​ ​ ​ ​ ​ ​ ​ Equipment and leasehold improvements, net ​ $ 4,541 ​ $ 3,286 ​ Accumulated depreciation ​ (2,259) ​ (1,947) ​ Total equipment and leasehold improvements, net ​ $ 2,282 ​ $ 1,339 ​ ​ ​ ​ ​ ​ ​ ​ Finance lease obligations ​ $ 891 ​ $ 539 ​ Finance lease obligations, less current portion ​ ​ 1,413 ​ ​ 778 ​ Total finance lease obligations ​ $ 2,304 ​ $ 1,317 ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average remaining lease term (in years): ​ ​ ​ ​ ​ ​ ​ Operating Leases ​ ​ 3.55 ​ ​ 3.79 ​ Finance Leases ​ ​ 2.65 ​ ​ 2.62 ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average discount rate: ​ ​ ​ ​ ​ ​ ​ Operating Leases ​ ​ 4.13 % ​ 4.28 % Finance Leases ​ ​ 2.57 % ​ 2.78 %
Summary of Other Information and Supplemental Cash Flow Information Related to Finance and Operating Leases	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Six Months Ended ​ ​ July 1, ​ July 2, ​ ​ 2022 2021 ​ ​ (in thousands) Cash paid for amounts included in the measurement of lease liabilities: ​ ​ ​ ​ ​ ​ Operating cash flow from operating leases ​ $ 3,273 ​ $ 3,477 Operating cash flow from finance leases ​ ​ 29 ​ ​ 13 Financing cash flow from finance leases ​ ​ 444 ​ ​ 214 ​ ​ ​ ​ ​ ​ ​ Right-of-use assets obtained in exchange for lease liabilities: ​ ​ ​ ​ ​ ​ Operating leases ​ $ 1,002 ​ $ 240
Summary of the Maturities of Operating Lease Liabilities	The following is a summary of the maturities of lease liabilities as of July 1, 2022: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating Finance ​ ​ (in thousands) ​ Fiscal year: ​ ​ ​ ​ ​ ​ ​ Remainder of 2022 ​ $ 3,117 ​ $ 522 ​ 2023 ​ 4,543 ​ 947 ​ 2024 ​ 3,030 ​ ​ 674 ​ 2025 ​ ​ 2,225 ​ ​ 157 ​ 2026 ​ ​ 2,159 ​ 73 ​ 2027 and thereafter ​ 453 ​ 7 ​ Total lease payments ​ ​ 15,527 ​ ​ 2,380 ​ Less: Imputed interest ​ (1,136) ​ ​ (76) ​ Total lease obligations ​ 14,391 ​ ​ 2,304 ​ Less: Current obligations ​ 5,435 ​ ​ 891 ​ Noncurrent lease obligations ​ $ 8,956 ​ $ 1,413 ​
Summary of the Maturities of Finance Lease Liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating Finance ​ ​ (in thousands) ​ Fiscal year: ​ ​ ​ ​ ​ ​ ​ Remainder of 2022 ​ $ 3,117 ​ $ 522 ​ 2023 ​ 4,543 ​ 947 ​ 2024 ​ 3,030 ​ ​ 674 ​ 2025 ​ ​ 2,225 ​ ​ 157 ​ 2026 ​ ​ 2,159 ​ 73 ​ 2027 and thereafter ​ 453 ​ 7 ​ Total lease payments ​ ​ 15,527 ​ ​ 2,380 ​ Less: Imputed interest ​ (1,136) ​ ​ (76) ​ Total lease obligations ​ 14,391 ​ ​ 2,304 ​ Less: Current obligations ​ 5,435 ​ ​ 891 ​ Noncurrent lease obligations ​ $ 8,956 ​ $ 1,413 ​

SEGMENT AND GEOGRAPHICAL INFO_2

SEGMENT AND GEOGRAPHICAL INFORMATION (Tables)	6 Months Ended
	Jul. 01, 2022
SEGMENT AND GEOGRAPHICAL INFORMATION
Schedule of financial information with respect to the reportable segments	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Engineering ​ Unallocated ​ ​ ​ ​ Consolidated ​ Energy & Consulting Corporate Intersegment Total ​ ​ (in thousands) Fiscal Three Months Ended July 1, 2022 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contract revenue ​ $ 84,675 ​ $ 17,970 ​ $ - ​ $ - ​ $ 102,645 Depreciation and amortization ​ ​ 4,183 ​ ​ 243 ​ ​ - ​ ​ - ​ ​ 4,426 Interest expense, net ​ ​ 1 ​ ​ - ​ ​ 1,029 ​ ​ - ​ ​ 1,030 Segment profit (loss) before income tax expense ​ ​ (6,357) ​ ​ 2,531 ​ ​ (2,173) ​ ​ - ​ ​ (5,999) Income tax expense (benefit) ​ ​ (1,891) ​ ​ 732 ​ ​ (514) ​ ​ - ​ ​ (1,673) Net income (loss) ​ ​ (4,467) ​ ​ 1,798 ​ ​ (1,657) ​ ​ - ​ ​ (4,326) Segment assets (1) ​ ​ 323,070 ​ ​ 23,293 ​ ​ 58,650 ​ ​ (23,130) ​ ​ 381,883 Fiscal Three Months Ended July 2, 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contract revenue ​ $ 66,447 ​ $ 17,707 ​ $ - ​ $ - ​ $ 84,154 Depreciation and amortization ​ ​ 3,973 ​ ​ 251 ​ ​ - ​ ​ - ​ ​ 4,224 Interest expense, net ​ ​ 1 ​ ​ - ​ ​ 1,098 ​ ​ - ​ ​ 1,099 Segment profit (loss) before income tax expense ​ ​ (4,913) ​ ​ 2,724 ​ ​ (6,075) ​ ​ - ​ ​ (8,264) Income tax expense (benefit) ​ ​ (2,151) ​ ​ 1,247 ​ ​ (2,759) ​ ​ - ​ ​ (3,663) Net income (loss) ​ ​ (2,762) ​ ​ 1,478 ​ ​ (3,317) ​ ​ - ​ ​ (4,601) Segment assets (1) ​ ​ 322,255 ​ ​ 22,952 ​ ​ 58,410 ​ ​ (23,130) ​ ​ 380,487 Fiscal Six Months Ended July 1, 2022 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contract revenue ​ $ 159,561 ​ $ 34,922 ​ $ - ​ $ - ​ $ 194,483 Depreciation and amortization ​ ​ 8,340 ​ ​ 495 ​ ​ - ​ ​ - ​ ​ 8,835 Interest expense, net ​ ​ 5 ​ ​ - ​ ​ 1,776 ​ ​ - ​ ​ 1,781 Segment profit (loss) before income tax expense ​ ​ (10,710) ​ ​ 4,638 ​ ​ (6,089) ​ ​ - ​ ​ (12,161) Income tax expense (benefit) ​ ​ (3,578) ​ ​ 1,549 ​ ​ (2,033) ​ ​ - ​ ​ (4,062) Net income (loss) ​ ​ (7,132) ​ ​ 3,088 ​ ​ (4,055) ​ ​ - ​ ​ (8,099) Segment assets (1) ​ ​ 323,070 ​ ​ 23,293 ​ ​ 58,650 ​ ​ (23,130) ​ ​ 381,883 Fiscal Six Months Ended July 2, 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contract revenue ​ $ 128,454 ​ $ 34,786 ​ $ - ​ $ - ​ $ 163,240 Depreciation and amortization ​ ​ 7,911 ​ ​ 500 ​ ​ - ​ ​ - ​ ​ 8,411 Interest expense, net ​ ​ 5 ​ ​ - ​ ​ 2,158 ​ ​ - ​ ​ 2,163 Segment profit (loss) before income tax expense ​ ​ (7,745) ​ ​ 4,834 ​ ​ (10,577) ​ ​ - ​ ​ (13,488) Income tax expense (benefit) ​ ​ (2,941) ​ ​ 1,836 ​ ​ (4,016) ​ ​ - ​ ​ (5,121) Net income (loss) ​ ​ (4,804) ​ ​ 2,999 ​ ​ (6,562) ​ ​ - ​ ​ (8,367) Segment assets (1) ​ ​ 322,255 ​ ​ 22,952 ​ ​ 58,410 ​ ​ (23,130) ​ ​ 380,487 (1) Segment assets are presented net of intercompany receivables.
Schedule of disaggregation of revenue	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended July 1, 2022 ​ Energy Engineering and Consulting Total ​ (in thousands) Contract Type ​ ​ ​ ​ ​ ​ ​ ​ ​ Time-and-materials ​ $ 7,587 ​ $ 13,340 ​ $ 20,927 Unit-based ​ ​ 42,544 ​ ​ 3,755 ​ ​ 46,299 Fixed price ​ ​ 34,545 ​ ​ 874 ​ ​ 35,419 Total (1) ​ $ 84,675 ​ $ 17,970 ​ $ 102,645 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Client Type ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ $ 6,701 ​ $ 1,476 ​ $ 8,177 Government ​ ​ 29,861 ​ ​ 16,338 ​ ​ 46,199 Utilities (2) ​ ​ 48,114 ​ ​ 156 ​ ​ 48,270 Total (1) ​ $ 84,675 ​ $ 17,970 ​ $ 102,645 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Geography (3) ​ ​ ​ ​ ​ ​ ​ ​ ​ Domestic ​ $ 84,675 ​ $ 17,970 ​ $ 102,645 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Six months ended July 1, 2022 ​ Energy Engineering and Consulting Total ​ (in thousands) Contract Type ​ ​ ​ ​ ​ ​ ​ ​ ​ Time-and-materials ​ $ 16,405 ​ $ 26,341 ​ $ 42,746 Unit-based ​ ​ 85,501 ​ ​ 6,739 ​ ​ 92,240 Fixed price ​ ​ 57,655 ​ ​ 1,842 ​ ​ 59,497 Total (1) ​ $ 159,561 ​ $ 34,922 ​ $ 194,483 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Client Type ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ $ 14,790 ​ $ 2,954 ​ $ 17,744 Government ​ ​ 48,220 ​ ​ 31,791 ​ ​ 80,011 Utilities (2) ​ ​ 96,551 ​ ​ 177 ​ ​ 96,728 Total (1) ​ $ 159,561 ​ $ 34,922 ​ $ 194,483 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Geography (3) ​ ​ ​ ​ ​ ​ ​ ​ ​ Domestic ​ $ 159,561 ​ $ 34,922 ​ $ 194,483 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended July 2, 2021 ​ Energy Engineering and Consulting Total ​ (in thousands) Contract Type ​ ​ ​ ​ ​ ​ ​ ​ ​ Time-and-materials ​ $ 9,056 ​ $ 13,863 ​ $ 22,919 Unit-based ​ ​ 41,604 ​ ​ 2,722 ​ ​ 44,326 Fixed price ​ ​ 15,786 ​ ​ 1,123 ​ ​ 16,909 Total (1) ​ $ 66,446 ​ $ 17,708 ​ $ 84,154 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Client Type ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ $ 7,016 ​ $ 1,372 ​ $ 8,388 Government ​ ​ 13,675 ​ ​ 16,281 ​ ​ 29,956 Utilities (2) ​ ​ 45,756 ​ ​ 55 ​ ​ 45,811 Total (1) ​ $ 66,446 ​ $ 17,708 ​ $ 84,154 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Geography (3) ​ ​ ​ ​ ​ ​ ​ ​ ​ Domestic ​ $ 66,446 ​ $ 17,708 ​ $ 84,154 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Six months ended July 2, 2021 ​ Energy Engineering and Consulting Total ​ (in thousands) Contract Type ​ ​ ​ ​ ​ ​ ​ ​ ​ Time-and-materials ​ $ 15,956 ​ $ 27,284 ​ $ 43,240 Unit-based ​ ​ 81,218 ​ ​ 5,167 ​ ​ 86,385 Fixed price ​ ​ 31,279 ​ ​ 2,336 ​ ​ 33,615 Total (1) ​ $ 128,453 ​ $ 34,787 ​ $ 163,240 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Client Type ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ $ 12,944 ​ $ 2,469 ​ $ 15,413 Government ​ ​ 27,229 ​ ​ 32,210 ​ ​ 59,439 Utilities (2) ​ ​ 88,280 ​ ​ 108 ​ ​ 88,388 Total (1) ​ $ 128,453 ​ $ 34,787 ​ $ 163,240 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Geography (3) ​ ​ ​ ​ ​ ​ ​ ​ ​ Domestic ​ $ 128,453 ​ $ 34,787 ​ $ 163,240 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) Amounts may not add to the totals due to rounding. (2) Includes the portion of revenue related to small business programs paid by the end user/customer. (3) Revenue from the Company’s foreign operations were not material for the three and six months ended July 1, 2022 and July 2, 2021.

EARNINGS PER SHARE (EPS) (Table

EARNINGS PER SHARE (EPS) (Tables)	6 Months Ended
	Jul. 01, 2022
EARNINGS PER SHARE (EPS)
Schedule of number of weighted-average common shares outstanding used to compute basic and diluted EPS	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended ​ Six months ended ​ ​ July 1, ​ July 2, ​ July 1, ​ July 2, ​ 2022 2021 2022 2021 ​ ​ (in thousands, except per share amounts) Net income (loss) ​ $ (4,326) ​ $ (4,601) ​ $ (8,099) ​ $ (8,367) Weighted-average common shares outstanding ​ 13,016 ​ 12,421 ​ 12,901 ​ 12,284 Effect of dilutive stock options and restricted stock awards ​ — ​ — ​ — ​ — Weighted-average common shares outstanding-diluted ​ 13,016 ​ 12,421 ​ 12,901 ​ 12,284 Earnings (Loss) per share: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic ​ $ (0.33) ​ $ (0.37) ​ $ (0.63) ​ $ (0.68) Diluted ​ $ (0.33) ​ $ (0.37) ​ $ (0.63) ​ $ (0.68)

ORGANIZATION AND OPERATIONS O_3

ORGANIZATION AND OPERATIONS OF THE COMPANY - Segment Information (Details)	6 Months Ended
	Jul. 01, 2022 segment
Segment Information
Number of reporting segments	2

ORGANIZATION AND OPERATIONS O_4

ORGANIZATION AND OPERATIONS OF THE COMPANY - Fiscal Years (Details)	3 Months Ended								12 Months Ended
	Dec. 30, 2022	Sep. 30, 2022	Jul. 01, 2022	Apr. 01, 2022	Dec. 31, 2021	Oct. 01, 2021	Jul. 02, 2021	Apr. 02, 2021	Dec. 30, 2022	Dec. 31, 2021
Entity Information [Line Items]
Length of fiscal period	91 days	91 days	91 days	91 days	91 days	91 days	91 days	91 days	364 days	364 days
Minimum [Member]
Entity Information [Line Items]
Length of fiscal period				91 days					364 days
Maximum [Member]
Entity Information [Line Items]
Length of fiscal period				98 days					371 days

ORGANIZATION AND OPERATIONS O_5

ORGANIZATION AND OPERATIONS OF THE COMPANY - Historical and Current Impact of Covid-19 (Details) - Covid-19 $ in Thousands		6 Months Ended	12 Months Ended
	Aug. 03, 2022 contract	Jul. 01, 2022 USD ($)	Dec. 31, 2021 contract	Dec. 31, 2020 contract
Unusual or Infrequent Item, or Both [Line Items]
Number of contracts cancelled | contract	0		0	0
Goodwill impairment		$ 0
Long-lived assets impairment		$ 0

RECENT ACCOUNTING PRONOUNCEME_3

RECENT ACCOUNTING PRONOUNCEMENTS (Details) - Accounting Standards Update 2021-01 [Member]	Jul. 01, 2022
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adopted	true
Change in Accounting Principle, Accounting Standards Update, Adoption Date	Mar. 08, 2022

REVENUES - Segment Information

REVENUES - Segment Information (Details)	6 Months Ended
	Jul. 01, 2022 segment
Segment Information
Number of reporting segments	2

REVENUES - General Information

REVENUES - General Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jul. 01, 2022	Jul. 02, 2021	Jul. 01, 2022	Jul. 02, 2021	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Payroll taxes, bonuses and employee benefit costs for all Company personnel	$ 20,439,000	$ 18,712,000	$ 39,796,000	$ 38,156,000
Revenue of the entity recorded in which it acts solely in the capacity of an agent			0
Retained accounts receivable	$ 6,400,000		$ 6,400,000
Accounts receivable
Disaggregation of Revenue [Line Items]
Retained accounts receivable					$ 4,500,000
Maximum [Member]
Disaggregation of Revenue [Line Items]
Percent of revenue (as a percent)	3%		3%
Minimum [Member]
Disaggregation of Revenue [Line Items]
Percent of revenue (as a percent)	2%		2%
Cost of Sales [Member]
Disaggregation of Revenue [Line Items]
Payroll taxes, bonuses and employee benefit costs for all Company personnel			$ 0
Allocation of facilities costs to contract revenue			$ 0

SUPPLEMENTAL FINANCIAL STATEM_3

SUPPLEMENTAL FINANCIAL STATEMENT DATA - Accounts Receivable (Details) $ in Millions	6 Months Ended
	Jul. 01, 2022 USD ($)
SUPPLEMENTAL FINANCIAL STATEMENT DATA
Cash proceeds from sale of trade receivables	$ 8
Discount on trade accounts receivable sold	$ 0.8

SUPPLEMENTAL FINANCIAL STATEM_4

SUPPLEMENTAL FINANCIAL STATEMENT DATA - Equipment and Leasehold Improvements, Net - Tabular Disclosure (Details) - USD ($) $ in Thousands	Jul. 01, 2022	Dec. 31, 2021
EQUIPMENT AND LEASEHOLD IMPROVEMENTS
Equipment under finance leases	$ 4,541	$ 3,286
Equipment and leasehold improvements, gross	45,340	39,891
Accumulated depreciation and amortization	(25,958)	(23,134)
Total equipment and leasehold improvements, net	19,382	16,757
Furniture and Fixtures [Member]
EQUIPMENT AND LEASEHOLD IMPROVEMENTS
Equipment and leasehold improvements	4,018	4,070
Computer Hardware and Software [Member]
EQUIPMENT AND LEASEHOLD IMPROVEMENTS
Equipment and leasehold improvements	30,659	26,425
Leasehold Improvements [Member]
EQUIPMENT AND LEASEHOLD IMPROVEMENTS
Equipment and leasehold improvements	3,011	3,011
Automobiles Trucks and Field Equipment [Member]
EQUIPMENT AND LEASEHOLD IMPROVEMENTS
Equipment and leasehold improvements	$ 3,111	$ 3,099

SUPPLEMENTAL FINANCIAL STATEM_5

SUPPLEMENTAL FINANCIAL STATEMENT DATA - Equipment and Leasehold Improvements, Net - Amortization Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 01, 2022	Jul. 02, 2021	Jul. 01, 2022	Jul. 02, 2021	Dec. 31, 2021
Finance leases
Amortization expense	$ 255	$ 135	$ 488	$ 258	$ 600

SUPPLEMENTAL FINANCIAL STATEM_6

SUPPLEMENTAL FINANCIAL STATEMENT DATA - Accrued Liabilities (Details) - USD ($) $ in Thousands	Jul. 01, 2022	Dec. 31, 2021
SUPPLEMENTAL FINANCIAL STATEMENT DATA
Accrued subcontractor costs	$ 22,938	$ 19,727
Other	4,263	2,750
Employee withholdings	2,943	2,665
Compensation and payroll taxes	2,546	2,244
Accrued bonuses	1,733	7,767
Accrued workers' compensation insurance	571	527
Total accrued liabilities	$ 34,994	$ 35,680

SUPPLEMENTAL FINANCIAL STATEM_7

SUPPLEMENTAL FINANCIAL STATEMENT DATA - Goodwill (Details) $ in Thousands	Jul. 01, 2022 USD ($)
Changes in carrying value of goodwill
Goodwill at beginning of period	$ 130,124
Goodwill at end of period	130,124
Energy
Changes in carrying value of goodwill
Goodwill at beginning of period	129,375
Goodwill at end of period	129,375
Engineering and Consulting
Changes in carrying value of goodwill
Goodwill at beginning of period	749
Goodwill at end of period	$ 749

SUPPLEMENTAL FINANCIAL STATEM_8

SUPPLEMENTAL FINANCIAL STATEMENT DATA - Finite-lived Intangible Assets - Gross Amounts and Accumulated Amortization (Details) - USD ($) $ in Thousands	Jul. 01, 2022	Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Total finite intangible assets	$ 99,234	$ 98,924
Accumulated Amortization	52,210	46,521
Order or Production Backlog [Member]
Finite-Lived Intangible Assets [Line Items]
Total finite intangible assets	7,944	7,944
Accumulated Amortization	7,655	7,222
Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Total finite intangible assets	15,911	15,911
Accumulated Amortization	9,993	8,997
Noncompete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Total finite intangible assets	1,420	1,420
Accumulated Amortization	1,420	1,413
Developed Technology Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Total finite intangible assets	15,810	15,500
Accumulated Amortization	10,411	8,950
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Total finite intangible assets	58,149	58,149
Accumulated Amortization	$ 22,731	$ 19,939

SUPPLEMENTAL FINANCIAL STATEM_9

SUPPLEMENTAL FINANCIAL STATEMENT DATA - Finite-lived Intangible Assets - Amortization Period (Details)	6 Months Ended
	Jul. 01, 2022
Order or Production Backlog [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization Period (in years)	1 year
Trade Names [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization Period (in years)	2 years 6 months
Trade Names [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization Period (in years)	6 years
Noncompete Agreements [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization Period (in years)	4 years
Noncompete Agreements [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization Period (in years)	5 years
Developed Technology Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization Period (in years)	8 years
Customer Relationships [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization Period (in years)	5 years
Customer Relationships [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization Period (in years)	8 years

SUPPLEMENTAL FINANCIAL STATE_10

SUPPLEMENTAL FINANCIAL STATEMENT DATA - Intangible Assets (Details) - USD ($) $ in Thousands	Jul. 01, 2022	Dec. 31, 2021
Intangible Assets, Gross (Excluding Goodwill) [Abstract]
Total finite intangible assets	$ 99,234	$ 98,924
In-process research and technology		310
Total intangible assets	$ 99,234	$ 99,234

SUPPLEMENTAL FINANCIAL STATE_11

SUPPLEMENTAL FINANCIAL STATEMENT DATA - In-process Research and Technology Reclassified (Details) $ in Millions	3 Months Ended
	Apr. 01, 2022 USD ($)
SUPPLEMENTAL FINANCIAL STATEMENT DATA
In-process research and technology reclassified to developed technology	$ 0.3

SUPPLEMENTAL FINANCIAL STATE_12

SUPPLEMENTAL FINANCIAL STATEMENT DATA - Developed Technology (Details) $ in Millions	3 Months Ended
	Apr. 01, 2022 USD ($)
Developed Technology Rights [Member]
Finite-Lived Intangible Assets [Line Items]
In-process research and technology reclassified to developed technology	$ 0.3

DERIVATIVE FINANCIAL INSTRUME_2

DERIVATIVE FINANCIAL INSTRUMENTS (Details) - Interest swap agreement - Cash flow hedge - USD ($) $ in Thousands	Jan. 31, 2022	Jan. 31, 2019
Derivative [Line Items]
Notional amount	$ 0	$ 35,000
Fixed rate (as a percent)		2.47%

DEBT OBLIGATIONS - Composition

DEBT OBLIGATIONS - Composition (Details) - USD ($) $ in Thousands	Jul. 01, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Total debt	$ 113,610	$ 101,161
Issuance costs and debt discounts	(470)	(587)
Subtotal	113,140	100,574
Notes Payable to Banks [Member] | Term A Loan [Member]
Debt Instrument [Line Items]
Total debt	70,000	75,000
Notes Payable to Banks [Member] | Delayed Draw Term Loan Facility [Member]
Debt Instrument [Line Items]
Total debt	42,500	24,000
Notes Payable, Other Payables [Member] | Other Debt [Member]
Debt Instrument [Line Items]
Total debt	$ 1,110	$ 2,161

DEBT OBLIGATIONS - Classificati

DEBT OBLIGATIONS - Classification (Details) - USD ($) $ in Thousands	Jul. 01, 2022	Dec. 31, 2021
Long-term Debt, Current and Noncurrent [Abstract]
Subtotal	$ 113,140	$ 100,574
Less current portion of long-term debt	16,019	15,036
Long-term debt portion	$ 97,121	$ 85,538

DEBT OBLIGATIONS - Credit Facil

DEBT OBLIGATIONS - Credit Facilities (Details) - Notes Payable to Banks [Member] $ in Millions					12 Months Ended
	Mar. 08, 2022	Apr. 30, 2021 USD ($)	Apr. 29, 2021 USD ($)	Jun. 26, 2019 USD ($)	Dec. 30, 2022	Jul. 01, 2022 USD ($)
Credit Agreement 2019 [Member]
Debt Instrument [Line Items]
Debt instrument, covenants, total leverage ratio, maximum permitted to maintain, through June 26, 2020				6
Debt instrument, covenants, total leverage ratio, maximum permitted to maintain, September 25, 2020				7.75
Debt instrument, covenants, total leverage ratio, maximum permitted to maintain, January 1, 2021				7.50
Debt instrument, covenants, total leverage ratio, maximum permitted to maintain, April 2, 2021				6.25
Debt instrument, covenants, total leverage ratio, maximum permitted to maintain, July 2, 2021				4
Debt instrument, covenants, total leverage ratio, maximum permitted to maintain, October 1, 2021 and thereafter				3.25
Debt instrument, covenants, total leverage ratio, maximum permitted to maintain, through June 30, 2021		4.50
Debt instrument, covenants, total leverage ratio, maximum permitted to maintain, through September 30, 2021		5.25
Debt instrument, covenants, total leverage ratio, maximum permitted to maintain, through December 30, 2021		4.50
Debt instrument, covenants, total leverage ratio, maximum permitted to maintain, through March 31, 2022		4.25
Debt instrument, covenants, total leverage ratio, maximum permitted to maintain, through June 30, 2022 and thereafter		3.25
Minimum fixed charge coverage ratio				1.20
Maximum capital expenditure, debt covenant		$ 15		$ 7
Minimum liquidity		10		5
Maximum aggregate amount of earn-out payments during Relief Period		$ 17	$ 7	7
Available funds from the Delayed Draw Term Loan						$ 20
Maximum capital expenditures during Relief Period						$ 20
Credit Agreement 2019 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Commitment fee (as a percent)	0.15%	0.15%
Credit Agreement 2019 [Member] | Minimum [Member] | Forecast [Member]
Debt Instrument [Line Items]
Commitment fee (as a percent)					0.15%
Credit Agreement 2019 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Commitment fee (as a percent)	0.45%	0.40%
Credit Agreement 2019 [Member] | Maximum [Member] | Forecast [Member]
Debt Instrument [Line Items]
Commitment fee (as a percent)					0.40%
Credit Agreement 2019 [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Spread on floating interest rate, interest period (as a percent)	0.10%
Credit Agreement 2019 [Member] | Base Rate [Member] | Forecast [Member]
Debt Instrument [Line Items]
Spread on floating interest rate, interest period (as a percent)					0.10%
Credit Agreement 2019 [Member] | Base Rate [Member] | Minimum [Member]
Debt Instrument [Line Items]
Spread on floating interest rate (as a percent)	0.125%	0.125%
Credit Agreement 2019 [Member] | Base Rate [Member] | Minimum [Member] | Forecast [Member]
Debt Instrument [Line Items]
Spread on floating interest rate (as a percent)					0.125%
Credit Agreement 2019 [Member] | Base Rate [Member] | Maximum [Member]
Debt Instrument [Line Items]
Spread on floating interest rate (as a percent)	1.50%	1.25%
Credit Agreement 2019 [Member] | Base Rate [Member] | Maximum [Member] | Forecast [Member]
Debt Instrument [Line Items]
Spread on floating interest rate (as a percent)					1.25%
Credit Agreement 2019 [Member] | London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member]
Debt Instrument [Line Items]
Spread on floating interest rate (as a percent)		1.125%
Interest rate (as a percent)		0%
Credit Agreement 2019 [Member] | London Interbank Offered Rate (LIBOR) [Member] | Maximum [Member]
Debt Instrument [Line Items]
Spread on floating interest rate (as a percent)		2.25%
Credit Agreement 2019 [Member] | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]
Debt Instrument [Line Items]
Spread on floating interest rate, interest period (as a percent)	0.15%
Credit Agreement 2019 [Member] | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] | Forecast [Member]
Debt Instrument [Line Items]
Spread on floating interest rate, interest period (as a percent)					0.15%
Credit Agreement 2019 [Member] | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] | Minimum [Member]
Debt Instrument [Line Items]
Spread on floating interest rate (as a percent)	1.125%
Interest rate (as a percent)	0%
Credit Agreement 2019 [Member] | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] | Minimum [Member] | Forecast [Member]
Debt Instrument [Line Items]
Spread on floating interest rate (as a percent)					1.125%
Interest rate (as a percent)					0%
Credit Agreement 2019 [Member] | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] | Maximum [Member]
Debt Instrument [Line Items]
Spread on floating interest rate (as a percent)	2.50%
Credit Agreement 2019 [Member] | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] | Maximum [Member] | Forecast [Member]
Debt Instrument [Line Items]
Spread on floating interest rate (as a percent)					2.25%
Term A Loan [Member]
Debt Instrument [Line Items]
Initial outstanding principal				100
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity				50
Letter of Credit [Member] | Minimum [Member]
Debt Instrument [Line Items]
Commitment fee (as a percent)	0.84%	0.84%
Letter of Credit [Member] | Minimum [Member] | Forecast [Member]
Debt Instrument [Line Items]
Commitment fee (as a percent)					0.84%
Letter of Credit [Member] | Maximum [Member]
Debt Instrument [Line Items]
Commitment fee (as a percent)	1.875%	1.688%
Letter of Credit [Member] | Maximum [Member] | Forecast [Member]
Debt Instrument [Line Items]
Commitment fee (as a percent)					1.688%
Delayed Draw Term Loan Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity				$ 50

LEASES - General information (D

LEASES - General information (Details) $ in Thousands	6 Months Ended
	Jul. 01, 2022 USD ($)
Leases
Operating lease, option to extend	true
Operating lease, option to terminate	true
Residual value guarantee	$ 0
Minimum [Member]
Leases
Operating lease, remaining lease term	1 year
Maximum [Member]
Leases
Operating lease, remaining lease term	8 years
Operating lease, extension term	5 years
Operating lease, terminate term	1 year

LEASES - Lease Expense (Details

LEASES - Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 01, 2022	Jul. 02, 2021	Jul. 01, 2022	Jul. 02, 2021	Dec. 31, 2021
Lease cost
Operating lease cost	$ 1,534	$ 1,653	$ 3,112	$ 3,345
Amortization of assets	255	135	488	258	$ 600
Interest on lease liabilities	15	7	29	13
Total net lease cost	$ 1,804	$ 1,795	$ 3,629	$ 3,616

LEASES - Consolidated Balance S

LEASES - Consolidated Balance Sheet (Details) - USD ($) $ in Thousands	Jul. 01, 2022	Dec. 31, 2021
Assets and Liabilities, Lessee [Abstract]
Right-of-use assets	$ 13,387	$ 15,177
Operating leases, lease liabilities
Lease liability	5,435	5,575
Lease liability, less current portion	8,956	10,768
Total lease liabilities	14,391	16,343
Finance leases (included in equipment and leasehold improvements, net):
Equipment and leasehold improvements	4,541	3,286
Accumulated depreciation	(2,259)	(1,947)
Total equipment and leasehold improvements, net	$ 2,282	$ 1,339
Finance Lease, Right-of-Use Asset, Statement of Financial Position	Equipment and leasehold improvements, net	Equipment and leasehold improvements, net
Finance lease obligations
Finance lease obligations	$ 891	$ 539
Finance lease obligations, less current portion	1,413	778
Total finance lease obligations	$ 2,304	$ 1,317

LEASES - Additional Information

LEASES - Additional Information (Details)	Jul. 01, 2022	Dec. 31, 2021
Leases
Operating leases, weighted average remaining lease term	3 years 6 months 18 days	3 years 9 months 14 days
Finance leases, weighted average remaining lease term	2 years 7 months 24 days	2 years 7 months 13 days
Operating leases, weighted average discount rate	4.13%	4.28%
Finance leases, weighted average discount rate	2.57%	2.78%

LEASES - Rent Expense (Details)

LEASES - Rent Expense (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 01, 2022	Jul. 02, 2021	Jul. 01, 2022	Jul. 02, 2021
LEASES
Rent expenses	$ 1.7	$ 3.3	$ 1.8	$ 3.6

LEASES - Supplemental Cash Flow

LEASES - Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	6 Months Ended
	Jul. 01, 2022	Jul. 02, 2021
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flow from operating leases	$ 3,273	$ 3,477
Operating cash flow from finance leases	29	13
Financing cash flow from finance leases	444	214
Right-of-use assets obtained in exchange for lease liabilities for operating leases	$ 1,002	$ 240

LEASES - Operating Leases - Mat

LEASES - Operating Leases - Maturities of Lease Liabilities (Details) $ in Thousands	Jul. 01, 2022 USD ($)
Operating
Remainder of 2022	$ 3,117
2023	4,543
2024	3,030
2025	2,225
2026	2,159
2027 and thereafter	453
Total lease payments	$ 15,527

LEASES - Operating Leases - Gro

LEASES - Operating Leases - Gross Difference (Details) - USD ($) $ in Thousands	Jul. 01, 2022	Dec. 31, 2021
Operating
Total lease payments	$ 15,527
Less: Imputed interest	(1,136)
Total lease liabilities	14,391	$ 16,343
Less: Current obligations	5,435	5,575
Noncurrent lease obligations	$ 8,956	$ 10,768

LEASES - Finance Leases - Matur

LEASES - Finance Leases - Maturities of Lease Liabilities (Details) $ in Thousands	Jul. 01, 2022 USD ($)
Finance
Remainder of 2022	$ 522
2023	947
2024	674
2025	157
2026	73
2027 and thereafter	7
Total lease payments	$ 2,380

LEASES - Finance Leases - Gross

LEASES - Finance Leases - Gross Difference (Details) - USD ($) $ in Thousands	Jul. 01, 2022	Dec. 31, 2021
Finance
Total lease payments	$ 2,380
Less: Imputed interest	(76)
Total finance lease obligations	2,304	$ 1,317
Less: Current obligations	891	539
Noncurrent lease obligations	$ 1,413	$ 778

COMMITMENTS AND VARIABLE INTE_2

COMMITMENTS AND VARIABLE INTEREST ENTITIES - Employee Benefit Plans (Details) $ in Millions	6 Months Ended
	Jul. 01, 2022 USD ($) Y	Jul. 02, 2021 USD ($)
Defined Contribution Plan Disclosure [Line Items]
Attained age | Y	21
Qualified Cash or Deferred Arrangement [Member]
Defined Contribution Plan Disclosure [Line Items]
Maximum employee contribution as a percentage of compensation under 401 (k) Plan	50%
Defined Contribution Plan, Tax Status	us-gaap:QualifiedPlanMember
Defined Contribution Plan [Member]
Defined Contribution Plan Disclosure [Line Items]
Service period	3 months
Defined contribution plan, employer matching contribution, percent of match	50%
Defined contribution plan, employer matching contribution, percent of employees' gross pay	6%
Employer matching contributions | $	$ 1.6	$ 1.3

COMMITMENTS AND VARIABLE INTE_3

COMMITMENTS AND VARIABLE INTEREST ENTITIES - Variable Interest Entities (Details)	6 Months Ended
	Jul. 01, 2022 item
COMMITMENTS AND VARIABLE INTEREST ENTITIES
Number of VIEs	1

SEGMENT AND GEOGRAPHICAL INFO_3

SEGMENT AND GEOGRAPHICAL INFORMATION - Segment Information (Details)	6 Months Ended
	Jul. 01, 2022 segment
Segment Information
Number of reporting segments	2

SEGMENT AND GEOGRAPHICAL INFO_4

SEGMENT AND GEOGRAPHICAL INFORMATION - Intersegment Sales (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2022	Jul. 02, 2021	Jul. 01, 2022	Jul. 02, 2021
Segment Reporting Information [Line Items]
Contract revenue	$ 102,645	$ 84,154	$ 194,483	$ 163,240
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Contract revenue	$ 0	$ 0	$ 0	$ 0

SEGMENT AND GEOGRAPHICAL INFO_5

SEGMENT AND GEOGRAPHICAL INFORMATION - Statement of Operations (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jul. 01, 2022	Apr. 01, 2022	Jul. 02, 2021	Apr. 02, 2021	Jul. 01, 2022	Jul. 02, 2021
Segment reconciliation
Contract revenue	$ 102,645		$ 84,154		$ 194,483	$ 163,240
Depreciation and amortization	4,426		4,224		8,835	8,411
Interest expense, net	1,030		1,099		1,781	2,163
Segment profit (loss) before income tax expense	(5,999)		(8,264)		(12,161)	(13,488)
Income tax expense (benefit)	(1,673)		(3,663)		(4,062)	(5,121)
Net income (loss)	(4,326)	$ (3,773)	(4,601)	$ (3,766)	(8,099)	(8,367)
Energy
Segment reconciliation
Contract revenue	84,675		66,446		159,561	128,453
Depreciation and amortization	4,183		3,973		8,340	7,911
Interest expense, net					5	5
Segment profit (loss) before income tax expense					(10,710)	(7,745)
Income tax expense (benefit)					(3,578)	(2,941)
Net income (loss)					(7,132)	(4,804)
Engineering and Consulting
Segment reconciliation
Contract revenue	17,970		17,708		34,922	34,787
Depreciation and amortization	243		251		495	500
Segment profit (loss) before income tax expense					4,638	4,834
Income tax expense (benefit)					1,549	1,836
Net income (loss)					3,088	2,999
Operating Segments [Member] | Energy
Segment reconciliation
Interest expense, net	1		1
Segment profit (loss) before income tax expense	(6,357)		(4,913)
Income tax expense (benefit)	(1,891)		(2,151)
Net income (loss)	(4,467)		(2,762)
Operating Segments [Member] | Engineering and Consulting
Segment reconciliation
Segment profit (loss) before income tax expense	2,531		2,724
Income tax expense (benefit)	732		1,247
Net income (loss)	1,798		1,478
Corporate, Non-Segment [Member]
Segment reconciliation
Interest expense, net	1,029		1,098		1,776	2,158
Segment profit (loss) before income tax expense	(2,173)		(6,075)		(6,089)	(10,577)
Income tax expense (benefit)	(514)		(2,759)		(2,033)	(4,016)
Net income (loss)	(1,657)		(3,317)		(4,055)	(6,562)
Intersegment Eliminations [Member]
Segment reconciliation
Contract revenue	$ 0		$ 0		$ 0	$ 0

SEGMENT AND GEOGRAPHICAL INFO_6

SEGMENT AND GEOGRAPHICAL INFORMATION - Segment Assets (Details) - USD ($) $ in Thousands	Jul. 01, 2022	Dec. 31, 2021	Jul. 02, 2021
Segment Reporting, Asset Reconciling Item [Line Items]
Segment assets	$ 381,883	$ 394,422	$ 380,487
Energy
Segment Reporting, Asset Reconciling Item [Line Items]
Segment assets	323,070		322,255
Engineering and Consulting
Segment Reporting, Asset Reconciling Item [Line Items]
Segment assets	23,293		22,952
Operating Segments [Member] | Energy
Segment Reporting, Asset Reconciling Item [Line Items]
Segment assets	323,070		322,255
Operating Segments [Member] | Engineering and Consulting
Segment Reporting, Asset Reconciling Item [Line Items]
Segment assets	23,293		22,952
Corporate, Non-Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Segment assets	58,650		58,410
Intersegment Eliminations [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Segment assets	$ (23,130)		$ (23,130)

SEGMENT AND GEOGRAPHICAL INFO_7

SEGMENT AND GEOGRAPHICAL INFORMATION - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2022	Jul. 02, 2021	Jul. 01, 2022	Jul. 02, 2021
Disaggregation of Revenue [Line Items]
Revenue	$ 102,645	$ 84,154	$ 194,483	$ 163,240
Domestic
Disaggregation of Revenue [Line Items]
Revenue	102,645	84,154	194,483	163,240
Energy
Disaggregation of Revenue [Line Items]
Revenue	84,675	66,446	159,561	128,453
Energy | Domestic
Disaggregation of Revenue [Line Items]
Revenue	84,675	66,446	159,561	128,453
Engineering and Consulting
Disaggregation of Revenue [Line Items]
Revenue	17,970	17,708	34,922	34,787
Engineering and Consulting | Domestic
Disaggregation of Revenue [Line Items]
Revenue	17,970	17,708	34,922	34,787
Commercial
Disaggregation of Revenue [Line Items]
Revenue	8,177	8,388	17,744	15,413
Commercial | Energy
Disaggregation of Revenue [Line Items]
Revenue	6,701	7,016	14,790	12,944
Commercial | Engineering and Consulting
Disaggregation of Revenue [Line Items]
Revenue	1,476	1,372	2,954	2,469
Government
Disaggregation of Revenue [Line Items]
Revenue	46,199	29,956	80,011	59,439
Government | Energy
Disaggregation of Revenue [Line Items]
Revenue	29,861	13,675	48,220	27,229
Government | Engineering and Consulting
Disaggregation of Revenue [Line Items]
Revenue	16,338	16,281	31,791	32,210
Utilities
Disaggregation of Revenue [Line Items]
Revenue	48,270	45,811	96,728	88,388
Utilities | Energy
Disaggregation of Revenue [Line Items]
Revenue	48,114	45,756	96,551	88,280
Utilities | Engineering and Consulting
Disaggregation of Revenue [Line Items]
Revenue	156	55	177	108
Time-and-materials
Disaggregation of Revenue [Line Items]
Revenue	20,927	22,919	42,746	43,240
Time-and-materials | Energy
Disaggregation of Revenue [Line Items]
Revenue	7,587	9,056	16,405	15,956
Time-and-materials | Engineering and Consulting
Disaggregation of Revenue [Line Items]
Revenue	13,340	13,863	26,341	27,284
Unit-based
Disaggregation of Revenue [Line Items]
Revenue	46,299	44,326	92,240	86,385
Unit-based | Energy
Disaggregation of Revenue [Line Items]
Revenue	42,544	41,604	85,501	81,218
Unit-based | Engineering and Consulting
Disaggregation of Revenue [Line Items]
Revenue	3,755	2,722	6,739	5,167
Fixed price
Disaggregation of Revenue [Line Items]
Revenue	35,419	16,909	59,497	33,615
Fixed price | Energy
Disaggregation of Revenue [Line Items]
Revenue	34,545	15,786	57,655	31,279
Fixed price | Engineering and Consulting
Disaggregation of Revenue [Line Items]
Revenue	$ 874	$ 1,123	$ 1,842	$ 2,336

SEGMENT AND GEOGRAPHICAL INFO_8

SEGMENT AND GEOGRAPHICAL INFORMATION - Geographical Information (Details)	Jul. 01, 2022 state
SEGMENT AND GEOGRAPHICAL INFORMATION
Number of states in which entity operates	23

SEGMENT AND GEOGRAPHICAL INFO_9

SEGMENT AND GEOGRAPHICAL INFORMATION - Concentration Risk (Details)	3 Months Ended		6 Months Ended
	Jul. 01, 2022	Jul. 02, 2021	Jul. 01, 2022	Jul. 02, 2021
Geographic Concentration Risk [Member] | Revenue from Contract with Customer Benchmark [Member] | CALIFORNIA
Concentration Risk [Line Items]
Concentration risk percentage	40.90%	34.80%	42.20%	34.50%
Geographic Concentration Risk [Member] | Revenue from Contract with Customer Benchmark [Member] | NEW YORK
Concentration Risk [Line Items]
Concentration risk percentage	19.60%	21.60%	20.20%	21.80%
Top Ten Customers, Three Months Ended July 1, 2022 | Customer Concentration Risk [Member] | Revenue from Contract with Customer Benchmark [Member]
Concentration Risk [Line Items]
Concentration risk percentage	55.40%
Top Ten Customers, Six Months Ended July 1, 2022 | Customer Concentration Risk [Member] | Revenue from Contract with Customer Benchmark [Member]
Concentration Risk [Line Items]
Concentration risk percentage			54.40%
Top Ten Customers, Three Months Ended July 2, 2021 | Customer Concentration Risk [Member] | Revenue from Contract with Customer Benchmark [Member]
Concentration Risk [Line Items]
Concentration risk percentage		48.40%
Top Ten Customers, Six Months Ended July 2, 2021 | Customer Concentration Risk [Member] | Revenue from Contract with Customer Benchmark [Member]
Concentration Risk [Line Items]
Concentration risk percentage				46.20%
Los Angeles Department of Water and Power | Customer Concentration Risk [Member] | Revenue from Contract with Customer Benchmark [Member]
Concentration Risk [Line Items]
Concentration risk percentage		14.60%	15.80%
Los Angeles Department of Water and Power | Customer Concentration Risk [Member] | Revenue from Contract with Customer, Segment Benchmark [Member] | Energy
Concentration Risk [Line Items]
Concentration risk percentage	17.60%		19.20%
Consolidated Edison of New York | Customer Concentration Risk [Member] | Revenue from Contract with Customer, Segment Benchmark [Member] | Energy
Concentration Risk [Line Items]
Concentration risk percentage		11.50%
Consolidated Edison of New York | Customer Concentration Risk [Member] | Revenue from Contract with Customer, Segment Benchmark [Member] | Engineering and Consulting
Concentration Risk [Line Items]
Concentration risk percentage				10.90%
City of Elk Grove | Customer Concentration Risk [Member] | Revenue from Contract with Customer, Segment Benchmark [Member] | Engineering and Consulting
Concentration Risk [Line Items]
Concentration risk percentage		13.90%		15.80%

INCOME TAXES - Valuation Allowa

INCOME TAXES - Valuation Allowance (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jul. 01, 2022	Dec. 31, 2021	Dec. 28, 2018	Jan. 01, 2021
Valuation Allowance [Line Items]
Increase (decrease) in valuation allowance	$ 0
Valuation allowance		$ 1,200		$ 86
California Franchise Tax Board [Member]
Valuation Allowance [Line Items]
Increase (decrease) in valuation allowance			$ 86
New Jersey Division of Taxation [Member]
Valuation Allowance [Line Items]
Increase (decrease) in valuation allowance		$ 1,100

INCOME TAXES - Uncertain Tax Po

INCOME TAXES - Uncertain Tax Positions (Details) $ in Thousands	Jul. 01, 2022 USD ($)
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued [Abstract]
Liability for uncertain tax positions	$ 0

INCOME TAXES - Income Tax Expen

INCOME TAXES - Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2022	Jul. 02, 2021	Jul. 01, 2022	Jul. 02, 2021
INCOME TAXES
Income tax expense (benefit)	$ (1,673)	$ (3,663)	$ (4,062)	$ (5,121)

INCOME TAXES - Examinations (De

INCOME TAXES - Examinations (Details) - New York State Division of Taxation and Finance [Member]	Jun. 10, 2021
Tax Year 2017 [Member]
Income Tax Examination [Line Items]
Income tax examination, year under examination	2017
Tax Year 2018 [Member]
Income Tax Examination [Line Items]
Income tax examination, year under examination	2018
Tax Year 2019 [Member]
Income Tax Examination [Line Items]
Income tax examination, year under examination	2019

EARNINGS PER SHARE (EPS) (Detai

EARNINGS PER SHARE (EPS) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jul. 01, 2022	Apr. 01, 2022	Jul. 02, 2021	Apr. 02, 2021	Jul. 01, 2022	Jul. 02, 2021
Net Income (Loss) Available to Common Stockholders, Diluted [Abstract]
Net income (loss)	$ (4,326)	$ (3,773)	$ (4,601)	$ (3,766)	$ (8,099)	$ (8,367)
Net income (loss) - basic	(4,326)		(4,601)		(8,099)	(8,367)
Net income (loss) - diluted	$ (4,326)		$ (4,601)		$ (8,099)	$ (8,367)
Weighted Average Number of Shares Outstanding, Diluted [Abstract]
Weighted-average common shares outstanding (in shares)	13,016		12,421		12,901	12,284
Weighted-average common shares outstanding-diluted (in shares)	13,016		12,421		12,901	12,284
Earnings Per Share, Diluted [Abstract]
Basic (in dollars per share)	$ (0.33)		$ (0.37)		$ (0.63)	$ (0.68)
Diluted (in dollars per share)	$ (0.33)		$ (0.37)		$ (0.63)	$ (0.68)

SUBSEQUENT EVENTS (Details)

SUBSEQUENT EVENTS (Details) - Notes Payable to Banks [Member] - Credit Agreement 2019 [Member] - USD ($) $ in Millions	Aug. 02, 2022	Jul. 01, 2022
Subsequent Event [Line Items]
Debt instrument, covenants, purchase money indebtedness and Capitalized Lease Obligations		$ 1.5
Subsequent Event
Subsequent Event [Line Items]
Debt instrument, covenants, purchase money indebtedness and Capitalized Lease Obligations	$ 4