Cash and cash equivalents at carrying value excluding amount funded.

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Line of credit receivable amount.

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Loan forgiveness period.

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Milestone payments eligible for achievement.

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Nature of business and basis of presentation.

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Payment for exclusivity and technology access fee.

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No definition available.

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Payment of milestone based amount.

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No definition available.

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Percentage of payroll to be utilized from proceeds.

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No definition available.

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Period of utilization of amount from promissory notes.

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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No definition available.

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The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Including the current and noncurrent portions, aggregate carrying amount of all types of notes payable, as of the balance sheet date, with initial maturities beyond one year or beyond the normal operating cycle, if longer.

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Amount of cash inflow from contractual arrangement with the lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

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The cash inflow from a contractual arrangement with the lender, including letter of credit, standby letter of credit and revolving credit arrangements, under which borrowings can be made up to a specific amount at any point in time with maturities due beyond one year or the operating cycle, if longer.

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The cash inflow from a borrowing supported by a written promise to pay an obligation.

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The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use.

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Nature of Business and Basis of Presentation - Additional Information (Details) - USD ($)						3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 05, 2020	Apr. 24, 2020	Apr. 20, 2020	Nov. 22, 2019	Nov. 05, 2019	Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2020	Apr. 30, 2019	Oct. 31, 2020	Oct. 31, 2019	Jun. 08, 2020
Nature Of Business And Basis Of Presentation [Line Items]
Research and development expenses						$ 1,141,000	$ 4,178,000	$ 2,296,000	$ 10,458,000
Unrestricted cash and cash equivalents						29,100,000		29,100,000			$ 9,400,000
Unrestricted cash and cash equivalents balance excluding amounts funded						4,500,000		4,500,000			9,400,000
Orion Energy Partners Investment Agent, LLC Credit Facility [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Proceeds from long-term lines of credit								$ 18,600,000			0
Orion Energy Partners Investment Agent, LLC Credit Facility [Member] \| Senior Secured Credit Facility [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Long-term line of credit											200,000,000.0
Orion Energy Partners Investment Agent, LLC Credit Facility [Member] \| Initial Funding [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Drew down to fully repay debt outstanding											14,500,000
Debt instrument term								7 years
Orion Energy Partners Investment Agent, LLC Credit Facility [Member] \| Second Funding [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Drew down to fully repay debt outstanding				$ 65,500,000
Orion Energy Partners Investment Agent, LLC Credit Facility [Member] \| Remainder of Funding [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Line of credit receivable amount											$ 120,000,000.0
Orion Energy Partners Investment Agent, LLC Credit Facility [Member] \| Remainder of Funding [Member] \| Maximum [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Line of credit receivable amount						120,000,000.0		$ 120,000,000.0
Orion Energy Partners Investment Agent, LLC Credit Facility [Member] \| Fifth Orion Amendment [Member] \| Subsequent Event [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Line of credit facility, maximum borrowing capacity												$ 35,000,000
PPP Note [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Net proceeds from promissory note		$ 6,500,000
Period of utilization of amount from promissory notes			56 days
Percentage of payroll to be utilized from proceeds			75.00%
Loan forgiveness period			56 days
Debt instrument term			2 years
Promissory note balance						$ 6,000,000.0		$ 6,000,000.0
PPP Note [Member] \| Minimum [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Percentage of payroll to be utilized from proceeds			75.00%
PPP Note [Member] \| Subsequent Event [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Percentage of payroll to be utilized from proceeds	60.00%
Loan forgiveness period	168 days
Debt instrument term	5 years
Joint Development Agreement [Member] \| Exxon Mobile Research And Engineering Company [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Payment for exclusivity and technology access fee					$ 5,000,000.0
Joint Development Agreement [Member] \| Maximum [Member] \| Exxon Mobile Research And Engineering Company [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Research and development expenses					45,000,000.0
Milestone-based payments					$ 10,000,000.0
Joint Development Agreement [Member] \| Scenario Forecast [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Milestone payments eligible for achievement										$ 5,000,000