Significant Accounting Policies (Policies)	9 Months Ended
Dec. 31, 2019
Accounting Policies [Abstract]
Use of Estimates, Policy [Policy Text Block]	Summary of Significant Accounting Policies We have identified the accounting policies and estimates that are critical to our business operations and understanding our results of operations. Those policies and estimates can be found in Note 1, “Summary of Significant Accounting Policies,” of the Notes to Consolidated Financial Statements and in “Critical Accounting Policies and Estimates,” in “Management's Discussion and Analysis of Financial Condition and Results of Operations” contained in our Annual Report on Form 10-K for the fiscal year ended March 31, 2019. Accordingly, this Quarterly Report on Form 10-Q should be read in conjunction with our Annual Report on Form 10-K for the fiscal year ended March 31, 2019. During the three and nine month periods ended December 31, 2019, there were no significant changes to any critical accounting policies or to the methodology used in determining estimates including those related to investment securities, inventories, goodwill, intangible assets, property and equipment, and contingencies. During the nine month period ended December 31, 2019, goodwill increased by $7,720 due to the purchase of Chengdu OK New Energy ("COKNE") partially offset by foreign currency translation.
Reclassification, Policy [Policy Text Block]	Reclassifications Certain amounts in the prior year consolidated financial statements have been reclassified to the current year presentation. The impact of the reclassifications made to prior year amounts is not material and did not affect net income.
New Accounting Pronouncements, Policy [Policy Text Block]	Relevant New Accounting Standards In 2016, the FASB issued ASU 2016-02, “Leases”. This guidance changes the requirements for inclusion of certain right-of-use assets and the associated liabilities to be included in a statement of financial position. The Company adopted this guidance effective April 1, 2019, using the modified retrospective method and utilized the optional transition method under which the Company will continue to apply the legacy guidance in Accounting Standards Codification (“ASC”) 840, including its disclosure requirements, in the comparative period presented. In addition, the Company elected the package of practical expedients permitted under the transition guidance which permits the following: a) carrying forward the historical lease classification, b) not separating lease components from non-lease components within the Company’s facility lease contracts, c) not presenting comparative periods but rather recording a cumulative catch-up during fiscal 2020, and d) electing, by asset class, not to record on the balance sheet a lease whose term is twelve months or less including reasonably certain renewal options. As a result of the adoption of ASU 2016-02 for the fiscal year beginning April 1, 2019, the Company recorded initial operating lease right-of-use assets of $18,351 and related operating lease liabilities of $18,053. Right-of-use assets are included in “Other assets” on the Company’s Balance Sheet as of December 31, 2019. Lease liabilities are classified as current and non-current, and are included in “Accrued expenses” and “Other liabilities”, respectively, on the Company’s Balance Sheet as of December 31, 2019. Please refer to Note 2 for additional information. In June 2016, the FASB issued ASU 2016-13, “Financial Instruments – Credit Losses: Measurements of Credit Losses on Financial Instruments.” This standard requires the measurement and recognition of expected credit losses held at amortized cost. This new standard replaces the use of forward-looking information to estimate credit losses and requires credit losses for available for sale debt securities to be recorded through an allowance for credit losses rather than a reduction in the amortized cost basis. This update is effective for public companies for annual reporting periods beginning after December 15, 2019. Management has performed a preliminary assessment of the potential impact of the adoption of ASU 2016-13, and believes that the financial impact would not be material. The adoption of the standard will result in additional disclosure requirements, and updating of our policies and procedures. The Company intends to adopt the standard utilizing the modified retrospective approach, effective April 1, 2020. In August 2017, the FASB issued ASU 2017-12, “Derivatives and Hedging.” The standard aims to align the designation and measurement guidance for qualifying hedging relationships and the presentation of hedge results for cash flow and fair value hedge accounting with risk management activities. The guidance is effective for public companies for annual reporting periods beginning after December 15, 2018, and interim periods within those annual periods. Additionally, in October 2018, the FASB issued ASU 2018-16, “Derivatives and Hedging (Topic 815): Inclusion of the Secured Overnight Financing Rate (SOFR) Overnight Index Swap (OIS) Rate as a Benchmark Interest Rate for Hedge Accounting Purposes”, which permits use of the OIS rate based on the SOFR as a U.S. benchmark interest rate for hedge accounting purposes under Topic 815. This update is effective for public companies for annual reporting periods beginning after December 15, 2018, and interim periods within those annual periods. For entities that had not yet adopted ASU 2017-12, the concurrent adoption of ASU 2018-16 is required. The Company concurrently adopted ASU 2017-12 and ASU 2018-16 effective April 1, 2019. The adoption of these standards has not had a material impact on our consolidated financial statements. In February 2018, the FASB issued ASU 2018-02, "Income Statement - Reporting Comprehensive Income." This standard allows a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act of 2017. The standard is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years and early adoption is permitted. The Company adopted ASU 2018-02 effective April 1, 2019 and elected to not reclassify the income tax effects of the Tax Cuts and Jobs Act from accumulated other comprehensive income to retained earnings. The adoption of this standard has not had a material impact on our consolidated financial statements. In August 2018, the FASB issued ASU 2018-13, “Fair Value Measurement – Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement.” This standard removes, adds and modifies certain disclosure requirements in the existing framework. ASU 2018-13 removes the following disclosure requirements: (i) the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy and (ii) the entity’s valuation processes for Level 3 fair value measurements. ASU 2018-13 adds the following disclosure requirements: (i) provide information about the measurement uncertainty of Level 3 fair value measurements as of the reporting date rather than a point in the future, (ii) disclose changes in unrealized gains and losses related to Level 3 measurements for the period included in other comprehensive income, and (iii) disclose for Level 3 measurements the range and weighted average of the significant unobservable inputs and the way it is calculated. ASU 2018-13 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. Early adoption is permitted. The Company does not expect this ASU to have a material impact on our consolidated financial statements and disclosures. In August 2018, the FASB issued ASU 2018-14, “Compensation – Retirement Benefits – Defined Benefit Plans – General.” This standard removes certain disclosures that are not considered cost beneficial, clarifies certain required disclosures and added additional disclosures. The standard is effective for fiscal years beginning after December 15, 2020, and early adoption is permitted. The amendments in ASU 2018-14 would need to be applied on a retrospective basis. Management is currently assessing the impact ASU 2018-14 will have on our disclosures. In August 2018, the FASB issued ASU 2018-15, “Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That is a Service Contract.” This guidance reduces the complexity for the accounting for costs of implementing a cloud computing service arrangement and aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). This update is effective for public companies for annual reporting periods beginning after December 15, 2019, and interim periods within those fiscal years. Early adoption is permitted. The Company early adopted this standard effective April 1, 2019, utilizing the prospective approach to all implementation costs incurred after the date of adoption. The adoption of ASU 2018-15 has not had a material impact on our consolidated financial statements. In December 2019, the FASB issued ASU 2019-12, "Income Taxes: Simplifying the Accounting for Income Taxes." This guidance removes certain exceptions to the general principles of ASC 740 in order to reduce the cost and complexity of its application. This guidance is effective for annual reporting periods beginning after December 15, 2020, including interim periods within those fiscal years, with certain amendments applied on a modified retrospective basis, with a cumulative-effect adjustment to retained earnings as of the beginning of the fiscal year of adoption, and others prospectively. Early adoption of this guidance is permitted, including the adoption in any interim period for public companies for which financial statements have not yet been issued. Management is currently assessing the impact ASU 2019-12 will have on our consolidated financial statements and disclosures. We have reviewed other newly issued accounting pronouncements and concluded that they are either not applicable to our business or that no material effect is expected on our consolidated financial statements as a result of future adoption.

Significant Accounting Policies (Policies)

9 Months Ended

Dec. 31, 2019

Use of Estimates, Policy [Policy Text Block]

Summary of Significant Accounting Policies

We have identified the accounting policies and estimates that are critical to our business operations and understanding our results of operations. Those policies and estimates can be found in Note 1, “Summary of Significant Accounting Policies,” of the Notes to Consolidated Financial Statements and in “Critical Accounting Policies and Estimates,” in “Management's Discussion and Analysis of Financial Condition and Results of Operations” contained in our Annual Report on Form 10-K for the fiscal year ended March 31, 2019. Accordingly, this Quarterly Report on Form 10-Q should be read in conjunction with our Annual Report on Form 10-K for the fiscal year ended March 31, 2019. During the three and nine month periods ended December 31, 2019, there were no significant changes to any critical accounting policies or to the methodology used in determining estimates including those related to investment securities, inventories, goodwill, intangible assets, property and equipment, and contingencies.

During the nine month period ended December 31, 2019, goodwill increased by $7,720 due to the purchase of Chengdu OK New Energy ("COKNE") partially offset by foreign currency translation.

Reclassification, Policy [Policy Text Block]

Reclassifications

Certain amounts in the prior year consolidated financial statements have been reclassified to the current year presentation. The impact of the reclassifications made to prior year amounts is not material and did not affect net income.

New Accounting Pronouncements, Policy [Policy Text Block]

Relevant New Accounting Standards

In 2016, the FASB issued ASU 2016-02, “Leases”. This guidance changes the requirements for inclusion of certain right-of-use assets and the associated liabilities to be included in a statement of financial position. The Company adopted this guidance effective April 1, 2019, using the modified retrospective method and utilized the optional transition method under which the Company will continue to apply the legacy guidance in Accounting Standards Codification (“ASC”) 840, including its disclosure requirements, in the comparative period presented. In addition, the Company elected the package of practical expedients permitted under the transition guidance which permits the following: a) carrying forward the historical lease classification, b) not separating lease components from non-lease components within the Company’s facility lease contracts, c) not presenting comparative periods but rather recording a cumulative catch-up during fiscal 2020, and d) electing, by asset class, not to record on the balance sheet a lease whose term is twelve months or less including reasonably certain renewal options. As a result of the adoption of ASU 2016-02 for the fiscal year beginning April 1, 2019, the Company recorded initial operating lease right-of-use assets of $18,351 and related operating lease liabilities of $18,053. Right-of-use assets are included in “Other assets” on the Company’s Balance Sheet as of December 31, 2019. Lease liabilities are classified as current and non-current, and are included in “Accrued expenses” and “Other liabilities”, respectively, on the Company’s Balance Sheet as of December 31, 2019. Please refer to Note 2 for additional information.

In June 2016, the FASB issued ASU 2016-13, “Financial Instruments – Credit Losses: Measurements of Credit Losses on Financial Instruments.” This standard requires the measurement and recognition of expected credit losses held at amortized cost. This new standard replaces the use of forward-looking information to estimate credit losses and requires credit losses for available for sale debt securities to be recorded through an allowance for credit losses rather than a reduction in the amortized cost basis. This update is effective for public companies for annual reporting periods beginning after December 15, 2019. Management has performed a preliminary assessment of the potential impact of the adoption of ASU 2016-13, and believes that the financial impact would not be material. The adoption of the standard will result in additional disclosure requirements, and updating of our policies and procedures. The Company intends to adopt the standard utilizing the modified retrospective approach, effective April 1, 2020.

In August 2017, the FASB issued ASU 2017-12, “Derivatives and Hedging.” The standard aims to align the designation and measurement guidance for qualifying hedging relationships and the presentation of hedge results for cash flow and fair value hedge accounting with risk management activities. The guidance is effective for public companies for annual reporting periods beginning after December 15, 2018, and interim periods within those annual periods. Additionally, in October 2018, the FASB issued ASU 2018-16, “Derivatives and Hedging (Topic 815): Inclusion of the Secured Overnight Financing Rate (SOFR) Overnight Index Swap (OIS) Rate as a Benchmark Interest Rate for Hedge Accounting Purposes”, which permits use of the OIS rate based on the SOFR as a U.S. benchmark interest rate for hedge accounting purposes under Topic 815. This update is effective for public companies for annual reporting periods beginning after December 15, 2018, and interim periods within those annual periods. For entities that had not yet adopted ASU 2017-12, the concurrent adoption of ASU 2018-16 is required. The Company concurrently adopted ASU 2017-12 and ASU 2018-16 effective April 1, 2019. The adoption of these standards has not had a material impact on our consolidated financial statements.

In February 2018, the FASB issued ASU 2018-02, "Income Statement - Reporting Comprehensive Income." This standard allows a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act of 2017. The standard is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years and early adoption is permitted. The Company adopted ASU 2018-02 effective April 1, 2019 and elected to not reclassify the income tax effects of the Tax Cuts and Jobs Act from accumulated other comprehensive income to retained earnings. The adoption of this standard has not had a material impact on our consolidated financial statements.

In August 2018, the FASB issued ASU 2018-13, “Fair Value Measurement – Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement.” This standard removes, adds and modifies certain disclosure requirements in the existing framework. ASU 2018-13 removes the following disclosure requirements: (i) the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy and (ii) the entity’s valuation processes for Level 3 fair value measurements. ASU 2018-13 adds the following disclosure requirements: (i) provide information about the measurement uncertainty of Level 3 fair value measurements as of the reporting date rather than a point in the future, (ii) disclose changes in unrealized gains and losses related to Level 3 measurements for the period included in other comprehensive income, and (iii) disclose for Level 3 measurements the range and weighted average of the significant unobservable inputs and the way it is calculated. ASU 2018-13 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. Early adoption is permitted. The Company does not expect this ASU to have a material impact on our consolidated financial statements and disclosures.

In August 2018, the FASB issued ASU 2018-14, “Compensation – Retirement Benefits – Defined Benefit Plans – General.” This standard removes certain disclosures that are not considered cost beneficial, clarifies certain required disclosures and added additional disclosures. The standard is effective for fiscal years beginning after December 15, 2020, and early adoption is permitted. The amendments in ASU 2018-14 would need to be applied on a retrospective basis. Management is currently assessing the impact ASU 2018-14 will have on our disclosures.

In August 2018, the FASB issued ASU 2018-15, “Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That is a Service Contract.” This guidance reduces the complexity for the accounting for costs of implementing a cloud computing service arrangement and aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). This update is effective for public companies for annual reporting periods beginning after December 15, 2019, and interim periods within those fiscal years. Early adoption is permitted. The Company early adopted this standard effective April 1, 2019, utilizing the prospective approach to all implementation costs incurred after the date of adoption. The adoption of ASU 2018-15 has not had a material impact on our consolidated financial statements.

In December 2019, the FASB issued ASU 2019-12, "Income Taxes: Simplifying the Accounting for Income Taxes." This guidance removes certain exceptions to the general principles of ASC 740 in order to reduce the cost and complexity of its application. This guidance is effective for annual reporting periods beginning after December 15, 2020, including interim periods within those fiscal years, with certain amendments applied on a modified retrospective basis, with a cumulative-effect adjustment to retained earnings as of the beginning of the fiscal year of adoption, and others prospectively. Early adoption of this guidance is permitted, including the adoption in any interim period for public companies for which financial statements have not yet been issued. Management is currently assessing the impact ASU 2019-12 will have on our consolidated financial statements and disclosures.

We have reviewed other newly issued accounting pronouncements and concluded that they are either not applicable to our business or that no material effect is expected on our consolidated financial statements as a result of future adoption.