Convertible Senior Notes [Policy Text Block]

Convertible Senior Notes

On June 22, 2022, the Company issued $375.0 million aggregate principal amount of its 2.5% convertible senior notes due 2027 (the “Notes”). The Notes were offered and sold in a private offering to qualified institutional buyers pursuant to Rule 144A under the Securities Act of 1933, as amended, pursuant to an indenture between the Company and U.S. Bank National Association, as trustee. Additionally, the Company granted the initial purchasers an option to purchase up to an additional $56.25 million aggregate principal amount of the Notes. The initial purchasers executed their option on June 27, 2022, and by that, increased the total aggregated principal amount of the Notes issued to $431.25 million. The Notes bear annual interest of 2.5%, payable semiannually in arrears on January 15 and July 15 of each year, beginning on January 15, 2023. The Notes mature on July 15, 2027, unless earlier converted, redeemed or repurchased and are the Company's senior unsecured obligations.

Holders of the Notes may convert all or any portion of their Notes at their option at any time prior to the close of business on the business day immediately preceding January 15, 2027 only under the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending on September 30, 2022 (and only during such calendar quarter), if the last reported sale price of the Company's common stock, par value $0.001 per share (the “Common Stock”), for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day (equivalent to an initial conversion price of approximately $90.27 per share of common stock); (2) during the five consecutive business day period immediately after any five consecutive trading day period (the “Measurement Period”) in which the trading price per $1,000 principal amount of Notes, as determined following a request by a holder or holders of the Notes for each trading day of the Measurement Period was less than 98% of the product of the last reported sale price of the Company's Common Stock and the conversion rate on each such trading day; (3) if the Company calls any or all of the Notes for redemption (the Company may not redeem the notes prior to July 21, 2025), at any time prior to the close of business on the second scheduled trading day prior to the redemption date, but only with respect to the Notes called (or deemed called) for redemption; or (4) upon the occurrence of specified corporate events. On or after January 15, 2027 until the close of business on the second scheduled trading day immediately preceding the maturity date, holders may convert all or any portion of their Notes at any time, regardless of the foregoing circumstances. Upon conversion, the Company will pay cash up to the aggregate principal amount of the Notes to be converted and pay or deliver, as the case may be, cash, shares of its common stock or a combination of cash and shares of its common stock, at its election, in respect of the remainder, if any, of its conversion obligation in excess of the aggregate principal amount of the Notes being converted.

The initial conversion rate was 11.0776 shares of common stock per $1,000 principal amount of Notes, which is equivalent to an initial conversion price of approximately $90.27 per share of common stock, subject to adjustment in certain events. In addition, following certain corporate events that occur prior to the maturity date or if the Company delivers a notice of redemption, it will, in certain circumstances, increase the conversion rate for a holder who elects to convert its Notes in connection with such a corporate event or notice of redemption, as the case may be. The Company may not redeem the notes prior to July 21, 2025. The Company may redeem for cash all or any portion of the Notes, at its option, on or after July 21, 2025 and on or before the 41st scheduled trading day immediately preceding the maturity date, if the last reported sale price of its common stock has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period (including the last trading day of such period) ending on, and including, the trading day immediately preceding the date on which we provide notice of redemption at a redemption price equal to 100% of the principal amount of the notes to be redeemed, plus accrued and unpaid interest, but excluding, the redemption date. No sinking fund is provided for the notes. Additionally, if the Company undergoes a fundamental change (other than certain exempted fundamental changes), holders may require the Company to repurchase for cash all or any portion of their Notes at a fundamental change repurchase price equal to 100% of the principal amount of the notes to be repurchased, plus accrued and unpaid interest.

The Company incurred approximately $11.6 million of issuance costs in respect of the issuance of the Notes, which were deferred and are presented as a reduction to the Notes principal amounts on the condensed consolidated balance sheets. The deferred issuance costs are amortized over the term of the Notes into interest expenses, net in the condensed consolidated statements of operations and comprehensive income. During the three and nine months ended September 30, 2022, $0.6 million was recorded as amortized issuance costs under interest expenses, net. The effective interest rate on the Notes, including the impact of the deferred debt issuance costs, is 3.1%.

Based on the closing market price of the Company's common stock on September 30, 2022, the if-converted value of the Notes was less than their aggregate principal amount.

Stockholders' Equity, Policy [Policy Text Block]

Purchase of Treasury Stock

In connection with the issuance of the Notes as described above, the Company used approximately $18.0 million of the net proceeds from the issuance of these Notes to repurchase 258,667 shares of its common stock in privately negotiated transactions at a price of $69.45 per share. The Company recorded this purchase of treasury stocks as a reduction to its equity on the condensed consolidated statements of equity in the second quarter of 2022.

Bank Loan [Policy Text Block]

Mizrahi Bank Loan

On April 12, 2022, the Company entered into a definitive loan agreement (the "Mizrahi Loan Agreement") with Mizrahi Tefahot Bank Ltd. (“Mizrahi Bank”). The Mizrahi Loan Agreement provides for a loan by Mizrahi Bank to the Company in an aggregate principal amount of $75.0 million (the “Mizrahi Loan”). The outstanding principal amount of the Mizrahi Loan will be repaid in 16 semi-annual payments of $4.7 million each, commencing on October 12, 2022. The duration of the Mizrahi Loan is 8 years. The Mizrahi Loan bears interest at a fixed rate of 4.1% per annum, payable semi-annually. The Mizrahi Loan Agreement includes various affirmative and negative covenants, including a requirement that the Company maintain (i) a financial debt to adjusted EBITDA ratio not to exceed 6.0, (ii) a minimum equity capital amount (as shown on its consolidated financial statements) of not less than $750 million, and (iii) an equity capital to total assets ratio of not less than 25%. The Mizrahi Loan Agreement includes other customary affirmative and negative covenants, including payment and covenant events of default.

Effect of COVID-19 Pandemic, Policy [Policy Text Block]

COVID-19 consideration

In March 2020, the World Health Organization declared the outbreak of the novel coronavirus ("COVID-19") a pandemic. Since that time and through the date of this quarterly report, the Company has implemented significant measures and continues to make efforts in order to meet government requirements and preserve the health and safety of its employees. The Company's preventative measures against COVID-19 and the recent spread of variant strains include working remotely when needed and adopting separate shifts in its power plants, manufacturing facilities and other locations while working to continue operations at close to full capacity in all locations. Since the end of the second quarter of 2021, the Company experienced an easing of government restrictions in areas it operates in, but uncertainty around the impact of COVID-19 continues in addition to supply chain challenges and rising interest rates. The Company has not laid-off or furloughed any employees due to COVID-19 and has continued to pay full salaries. In addition, the Company focused efforts on adjusting its operations to mitigate the impact of COVID-19 including managing its global supply chain risks and enhancing its liquidity profile. As most of the Company's electricity revenues are generated under long term contracts, the majority of which are under a fixed energy rate, the impact of COVID-19 on electricity revenues was limited.

In the Product segment, the Company experienced a significant decline in product backlog, which it believes resulted mainly due to the impact of COVID-19 outbreaks, which resulted in the extended shutdown of certain businesses in certain regions, delays in the supply and increases in the cost of raw materials and components that we purchased for our equipment manufacturing, and increases in the cost of marine transportation. The cost increases limited our ability to secure new purchase orders from potential customers and led to a reduction in our operating margins, which in turn negatively impacted our profitability.Over the last few months we have experienced higher demand for our product segment resulting in increased backlog and improved profitability.

In the Energy Storage segment, revenues are generated primarily from participating in the energy and ancillary services markets and therefore are directly impacted by the prevailing energy prices in those markets. We have experienced and are experiencing supply chain difficulties, as well as an increase in the cost of raw materials and batteries, which may impact our ability to complete the projects on time, and increases overall project costs.

While the extent and duration of the economic downturn from the COVID-19 pandemic remains unclear, the Company has considered, among other things, whether the global operational disruptions indicate a change in circumstances that may trigger asset impairments and whether it needs to revisit accounting estimates and projections or its expectations about collectability of receivables. Additionally, the Company has considered the potential impacts on its fair value disclosures and on its internal control over financial reporting and while significant uncertainty still exists concerning the magnitude of the impact and duration of the COVID-19 pandemic on the global economy, the Company has determined that there was no triggering event for an impairment with respect to any of its assets nor has there been an adverse change in the probability related to the collectability of its receivables. The Company continues to assess the potential impact of the global economic situation on its consolidated financial statements.

Exploratory Drilling Costs Capitalization and Impairment, Policy [Policy Text Block]

Write-offs of unsuccessful exploration activities

During the three and nine months ended September 30, 2022, the Company wrote-off approximately $0.8 million relating to exploration activities it decided to no longer pursue. There were no write-offs of unsuccessful exploration activities for the three and nine months ended September 30, 2021.

Concentration Risk, Credit Risk, Policy [Policy Text Block]

Concentration of credit risk

Financial instruments that potentially subject the Company to a concentration of credit risk consist principally of cash investments, marketable securities and accounts receivable.

The Company places its cash investments with high credit quality financial institutions located in the United States (“U.S.”) and in foreign countries. At September 30, 2022 and December 31, 2021, the Company had deposits totaling $31.6 million and $31.0 million, respectively, in ten U.S. financial institutions that were federally insured up to $250,000 per account. At September 30, 2022 and December 31, 2021, the Company’s deposits in foreign countries amounted to approximately $86.1 million and $64.3 million, respectively.

At September 30, 2022 and December 31, 2021, accounts receivable related to operations in foreign countries amounted to approximately $76.7 million and $77.5 million, respectively. At September 30, 2022 and December 31, 2021, accounts receivable from the Company’s primary customers, which each accounted for revenues in excess of 10% of total consolidated revenues for the related period, amounted to approximately 55% and 58% of the Company’s trade receivables, respectively.

The Company's revenues from its primary customers as a percentage of total revenues are as follows:

	Three Months Ended September 30,						Nine Months Ended September 30,
	2022			2021			2022			2021
Southern California Public Power Authority (“SCPPA”)		18.7	%		21.3	%		21.4	%		23.9	%
Sierra Pacific Power Company and Nevada Power Company		14.0			15.8			17.1			18.7
Kenya Power and Lighting Co. Ltd. ("KPLC")		15.2			16.1			14.9			16.3

The Company has historically been able to collect on substantially all of its receivable balances. As of September 30, 2022, the amount overdue from KPLC in Kenya was $20.6 million of which $2.7 million was paid in October 2022. The Company believes it will be able to collect all past due amounts in Kenya. This belief is supported by the fact that in addition to KPLC's obligations under its power purchase agreement, the Company holds a support letter from the Government of Kenya that covers certain cases of KPLC non-payment (such as where caused by government actions and/or political events).

In Honduras, as of September 30, 2022, the total amount overdue from Empresa Nacional de Energía Eléctrica ("ENEE") was $15.6 million of which none was paid to-date. In addition, due to continuing restrictive measures related to the COVID-19 pandemic in Honduras, the Company may experience further delays in collection. The Company believes it will be able to collect all past due amounts in Honduras.

The Company may experience delays in collection in other locations due to the restrictive measures related to the COVID-19 pandemic which were imposed globally to different extents.

See Note 4 - Marketable Securities and under the caption "Marketable Securities" below for additional information regarding investment in marketable securities.

Revenue [Policy Text Block]

Revenues from contracts with customers

Contract assets related to our Product segment reflect revenue recognized and performance obligations satisfied in advance of customer billing. Contract liabilities related to the Company's Product segment reflect payments received in advance of the satisfaction of performance under the contract. The Company receives payments from customers based on the terms established in the contracts. Total contract assets and contract liabilities as of September 30, 2022 and December 31, 2021 are as follows:

	September 30,			December 31,
	2022			2021
	(Dollars in thousands)
Contract assets (*)	$	17,354		$	9,692
Contract liabilities (*)	$	(14,034	)	$	(9,248	)

(*) Contract assets and contract liabilities are presented as "Costs and estimated earnings in excess of billings on uncompleted contracts" and "Billings in excess of costs and estimated earnings on uncompleted contracts", respectively, on the condensed consolidated balance sheets. The contract liabilities balance at the beginning of the year was not yet fully recognized as product revenues during the nine months ended September 30, 2022 as a result of performance obligations having not been fully satisfied yet.

On September 30, 2022, the Company had approximately $136.2 million of remaining performance obligations not yet satisfied or partly satisfied related to our Product segment. The Company expects to recognize approximately 100% of this amount as Product revenues during the next 24 months.

Disaggregated revenues from contracts with customers for the three and nine months ended September 30, 2022 and 2021 are disclosed under Note 9 - Business Segments, to the condensed consolidated financial statements.

Marketable Securities, Policy [Policy Text Block]

Marketable securities

The Company’s investments in marketable securities consisted of debt securities with maturity of up to one year and a high credit rating. The investments in marketable securities was classified as available-for-sale ("AFS") and thus measured at fair value based on quoted market prices. Unrealized gains and losses from AFS debt securities were excluded from earnings and reported net of the related tax effect in "Accumulated other comprehensive income (loss)". Realized gains and losses from sale of marketable securities, as determined on a specific identification basis, as well as interest income earned, were included in earnings. The Company considers available evidence in evaluating potential impairments of its investments, including credit market conditions, credit ratings of the security as well as the extent to which fair value is less than amortized cost. The Company estimates the lifetime expected credit losses for all AFS debt securities in an unrealized loss position under its allowance for credit losses model. The Company assesses the security’s credit indicators, including credit ratings when estimating a security’s probability of default. If the assessment indicates that an expected credit loss exists, the Company determines the portion of the unrealized loss attributable to credit deterioration and records an allowance for the expected credit loss in earnings. Unrealized gains and losses attributable to non-credit factors were recorded in "Accumulated other comprehensive income (loss)", net of tax. Marketable debt securities with original maturities of three months or less that are readily convertible into a known amount of cash are presented under "Cash and cash equivalents" in the condensed consolidated balance sheets.