Summary of Significant Accounting Policies and Other Information (Policies)	9 Months Ended
Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Consolidation	The consolidated financial statements include the accounts of Power Solutions International, Inc. and its wholly-owned subsidiaries and majority-owned subsidiaries in which the Company exercises control. The foregoing financial information was prepared in accordance with generally accepted accounting principles in the United States (“U.S. GAAP”) and rules and regulations of the SEC for interim financial reporting. All intercompany balances and transactions have been eliminated in consolidation.
Basis of Presentation	Certain information and note disclosures normally included in the Company’s annual financial statements prepared in accordance with U.S. GAAP have been condensed or omitted. The accompanying consolidated financial statements should be read in conjunction with, and have been prepared in accordance with accounting policies reflected in, the consolidated financial statements and related notes, included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020 (“the 2020 Annual Report”). The Company’s significant accounting policies are described in the aforementioned 2020 Annual Report. Included below are certain updates to those policies. The accompanying interim financial information is unaudited; however, the Company believes the financial information reflects all adjustments (consisting of items of a normal recurring nature) necessary for a fair presentation of financial position, results of operations and cash flows in conformity with U.S. GAAP. Operating results for interim periods are not necessarily indicative of annual operating results.
Use of Estimates	The preparation of consolidated financial statements in conformity with U.S. GAAP requires that management 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 and the reported amounts of revenue and expenses during the reporting period. Significant estimates and assumptions include the valuation of allowances for uncollectible receivables, inventory reserves, warranty reserves, evaluation of goodwill, other intangibles, property, plant and equipment for impairment, and determination of useful lives of long-lived assets. Actual results could materially differ from those estimates.
Research and Development	R&D expenses are expensed when incurred. R&D expenses consist primarily of wages, materials, testing and consulting related to the development of new engines, parts and applications.
Restricted Cash	The Company is required to maintain minimum levels of cash collateral to support the letters of credit. The cash collateral is held in a separate bank account which the Company is restricted from accessing.
Inventories	The Company’s inventories consist primarily of engines and parts. Engines are valued at the lower of cost plus estimated freight-in or net realizable value. Parts are valued at the lower of cost or net realizable value. Net realizable value approximates replacement cost. Cost is principally determined using the first-in, first-out method and includes material, labor and manufacturing overhead. It is the Company’s policy to review inventories on a continuing basis for obsolete, excess and slow-moving items and to record valuation adjustments for such items in order to eliminate non-recoverable costs from inventory. Valuation adjustments are recorded in an inventory reserve account and reduce the cost basis of the inventory in the period in which the reduced valuation is determined. Inventory reserves are established based on quantities on hand, usage and sales history, customer orders, projected demand and utilization within a current or future power system. Specific analysis of individual items or groups of items is performed based on these same criteria, as well as on changes in market conditions or any other identified conditions.
Warranty Costs	The Company offers a standard limited warranty on the workmanship of its products that in most cases covers defects for a defined period. Warranties for certified emission products are mandated by the U.S. Environmental Protection Agency (the “EPA”) and/or the California Air Resources Board (the “CARB”) and are longer than the Company’s standard warranty on certain emission related products. The Company’s products also carry limited warranties from suppliers. The Company’s warranties generally apply to engines fully manufactured by the Company and to the modifications the Company makes to supplier base products. Costs related to supplier warranty claims are generally borne by the supplier and passed through to the end customer. Warranty estimates are based on historical experience and represent the projected cost associated with the product. A liability and related expense are recognized at the time products are sold. The Company adjusts estimates when it is determined that actual costs may differ from initial or previous estimates. The Company’s warranty liability is generally affected by failure rates, repair costs, and the timing of failures. Future events and circumstances related to these factors could materially change the estimates and require adjustments to the warranty liability. In addition, new product launches require a greater use of judgment in developing estimates until historical experience becomes available.
Recently Issued Accounting Pronouncements - Adopted and Not Yet Adopted	Recently Issued Accounting Pronouncements – Adopted In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of Effects of Reference Rate Reform on Financial Reporting, which provided optional guidance for a limited period of time to ease the potential burden in accounting for (or recognizing the effects of) reference rate reform on financial reporting. The amendment allows entities to elect not to apply certain modification accounting requirements to contracts affected by reference rate reform if certain criteria are met. An entity that makes this election would not have to remeasure the contracts at the modification date or reassess a previous accounting determination. Entities can elect various optional expedients that would allow them to continue applying hedge accounting for hedging relationships affected by reference rate reform, if certain criteria are met. The guidance was effective upon issuance and expires after December 31, 2022. There was no impact on the Company’s Consolidated Balance Sheets, Statements of Operations, Statements of Cash Flows or Statement of Stockholders’ (Deficit) Equity as a result of this guidance. The Company continues to monitor contracts potentially impacted by reference rate reform, including the Company’s debt agreements, and will continue to assess the potential impacts of this guidance as reference rates are updated. Recently Issued Accounting Pronouncements – Not Yet Adopted In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses: Measurement of Credit Losses on Financial Instruments, which applies primarily to the Company’s accounts receivable impairment loss allowances. The guidance provides a revised model whereby the current expected credit losses are used to compute impairment of financial instruments. The new model requires evaluation of historical experience and various current and expected factors, which may affect the estimated amount of losses and requires determination of whether the affected financial instruments should be grouped in units of account. The guidance, as originally issued, was effective for fiscal years beginning after December 15, 2019. In November 2019, the FASB issued ASU 2019-10, Financial Instruments – Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842) Effective Dates, which deferred the effective dates of these standards for certain entities. Based on the guidance, the effective date of ASU 2016-13 is deferred for the Company until fiscal year 2023. The Company currently plans to adopt the guidance on January 1, 2023 when it becomes effective. The Company is continuing to assess the impact of the standard on its consolidated financial statements.
Revenue	Most of the Company’s contracts are for a period of less than one year; however, certain long-term manufacturing and extended warranty contracts extend beyond one year. The timing of revenue recognition may differ from the time of invoicing to customers and these timing differences result in contract assets, or contract liabilities, on the Company’s Consolidated Balance Sheet. Contract assets include amounts related to the contractual right to consideration for completed performance when the right to consideration is conditional. The Company records contract liabilities when cash payments are received or due in advance of performance. Contract assets and contract liabilities are recognized at the contract level.
Fair Value of Financial Instruments	Current Assets Cash and cash equivalents are measured at carrying value, which approximates fair value because of the short-term maturities of these instruments. Debt The Company measured its revolving credit facility and other short-term financing at original carrying value. Unamortized financing costs and deferred fees on the revolving credit facility are classified in Prepaid expenses and other current assets on the Consolidated Balance Sheet. The fair value of the revolving credit facility and other short-term financing approximated carrying value, as it consisted primarily of short-term variable rate loans.

Summary of Significant Accounting Policies and Other Information (Policies)

9 Months Ended

Sep. 30, 2021

Organization, Consolidation and Presentation of Financial Statements [Abstract]

The consolidated financial statements include the accounts of Power Solutions International, Inc. and its wholly-owned subsidiaries and majority-owned subsidiaries in which the Company exercises control. The foregoing financial information was prepared in accordance with generally accepted accounting principles in the United States (“U.S. GAAP”) and rules and regulations of the SEC for interim financial reporting. All intercompany balances and transactions have been eliminated in consolidation.

Basis of Presentation

Certain information and note disclosures normally included in the Company’s annual financial statements prepared in accordance with U.S. GAAP have been condensed or omitted. The accompanying consolidated financial statements should be read in conjunction with, and have been prepared in accordance with accounting policies reflected in, the consolidated financial statements and related notes, included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020 (“the 2020 Annual Report”). The Company’s significant accounting policies are described in the aforementioned 2020 Annual Report. Included below are certain updates to those policies. The accompanying interim financial information is unaudited; however, the Company believes the financial information reflects all adjustments (consisting of items of a normal recurring nature) necessary for a fair presentation of financial position, results of operations and cash flows in conformity with U.S. GAAP. Operating results for interim periods are not necessarily indicative of annual operating results.

Use of Estimates

The preparation of consolidated financial statements in conformity with U.S. GAAP requires that management 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 and the reported amounts of revenue and expenses during the reporting period. Significant estimates and assumptions include the valuation of allowances for uncollectible receivables, inventory reserves, warranty reserves, evaluation of goodwill, other intangibles, property, plant and equipment for impairment, and determination of useful lives of long-lived assets. Actual results could materially differ from those estimates.

Research and Development

R&D expenses are expensed when incurred. R&D expenses consist primarily of wages, materials, testing and consulting related to the development of new engines, parts and applications.

Restricted Cash

The Company is required to maintain minimum levels of cash collateral to support the letters of credit. The cash collateral is held in a separate bank account which the Company is restricted from accessing.

Inventories

The Company’s inventories consist primarily of engines and parts. Engines are valued at the lower of cost plus estimated freight-in or net realizable value. Parts are valued at the lower of cost or net realizable value. Net realizable value approximates replacement cost. Cost is principally determined using the first-in, first-out method and includes material, labor and manufacturing overhead. It is the Company’s policy to review inventories on a continuing basis for obsolete, excess and slow-moving items and to record valuation adjustments for such items in order to eliminate non-recoverable costs from inventory. Valuation adjustments are recorded in an inventory reserve account and reduce the cost basis of the inventory in the period in which the reduced valuation is determined. Inventory reserves are established based on quantities on hand, usage and sales history, customer orders, projected demand and utilization within a current or future power system. Specific analysis of individual items or groups of items is performed based on these same criteria, as well as on changes in market conditions or any other identified conditions.

Warranty Costs

The Company offers a standard limited warranty on the workmanship of its products that in most cases covers defects for a defined period. Warranties for certified emission products are mandated by the U.S. Environmental Protection Agency (the “EPA”) and/or the California Air Resources Board (the “CARB”) and are longer than the Company’s standard warranty on certain emission related products. The Company’s products also carry limited warranties from suppliers. The Company’s warranties generally apply to engines fully manufactured by the Company and to the modifications the Company makes to supplier base products. Costs related to supplier warranty claims are generally borne by the supplier and passed through to the end customer.

Warranty estimates are based on historical experience and represent the projected cost associated with the product. A liability and related expense are recognized at the time products are sold. The Company adjusts estimates when it is determined that actual costs may differ from initial or previous estimates. The Company’s warranty liability is generally affected by failure rates, repair costs, and the timing of failures. Future events and circumstances related to these factors could materially change the estimates and require adjustments to the warranty liability. In addition, new product launches require a greater use of judgment in developing estimates until historical experience becomes available.

Recently Issued Accounting Pronouncements - Adopted and Not Yet Adopted

Recently Issued Accounting Pronouncements – Adopted

In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of Effects of Reference Rate Reform on Financial Reporting, which provided optional guidance for a limited period of time to ease the potential burden in accounting for (or recognizing the effects of) reference rate reform on financial reporting. The amendment allows entities to elect not to apply certain modification accounting requirements to contracts affected by reference rate reform if certain criteria are met. An entity that makes this election would not have to remeasure the contracts at the modification date or reassess a previous accounting determination. Entities can elect various optional expedients that would allow them to continue applying hedge accounting for hedging relationships affected by reference rate reform, if certain criteria are met. The guidance was effective upon issuance and expires after December 31, 2022. There was no impact on the Company’s Consolidated Balance Sheets, Statements of Operations, Statements of Cash Flows or Statement of Stockholders’ (Deficit) Equity as a result of this guidance. The Company continues to monitor contracts potentially impacted by reference rate reform, including the Company’s debt agreements, and will continue to assess the potential impacts of this guidance as reference rates are updated.

Recently Issued Accounting Pronouncements – Not Yet Adopted

In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses: Measurement of Credit Losses on Financial Instruments, which applies primarily to the Company’s accounts receivable impairment loss allowances. The guidance provides a revised model whereby the current expected credit losses are used to compute impairment of financial instruments. The new model requires evaluation of historical experience and various current and expected factors, which may affect the estimated amount of losses and requires determination of whether the affected financial instruments should be grouped in units of account. The guidance, as originally issued, was effective for fiscal years beginning after December 15, 2019. In November 2019, the FASB issued ASU 2019-10, Financial Instruments – Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842) Effective Dates, which deferred the effective dates of these standards for certain entities. Based on the guidance, the effective date of ASU 2016-13 is deferred for the Company until fiscal year 2023. The Company currently plans to adopt the guidance on January 1, 2023 when it becomes effective. The Company is continuing to assess the impact of the standard on its consolidated financial statements.

Revenue

Most of the Company’s contracts are for a period of less than one year; however, certain long-term manufacturing and extended warranty contracts extend beyond one year. The timing of revenue recognition may differ from the time of invoicing to customers and these timing differences result in contract assets, or contract liabilities, on the Company’s Consolidated Balance Sheet. Contract assets include amounts related to the contractual right to consideration for completed performance when the right to consideration is conditional. The Company records contract liabilities when cash payments are received or due in advance of performance. Contract assets and contract liabilities are recognized at the contract level.

Fair Value of Financial Instruments

Current Assets

Cash and cash equivalents are measured at carrying value, which approximates fair value because of the short-term maturities of these instruments.

Debt

The Company measured its revolving credit facility and other short-term financing at original carrying value. Unamortized financing costs and deferred fees on the revolving credit facility are classified in Prepaid expenses and other current assets on the Consolidated Balance Sheet. The fair value of the revolving credit facility and other short-term financing approximated carrying value, as it consisted primarily of short-term variable rate loans.