Share based compensation arrangement by share based payment award options grants in period total fair value.

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Exercise price per share or per unit of warrants or rights outstanding.

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Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

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Amount of cost to be recognized for option under share-based payment arrangement.

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Amount of tax benefit for recognition of expense of award under share-based payment arrangement.

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Amount of cash inflow from issuance of shares under share-based payment arrangement. Includes, but is not limited to, option exercised.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Number of shares authorized for issuance under share-based payment arrangement.

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Gross number of share options (or share units) granted during the period.

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No definition available.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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Percentage of vesting of award under share-based payment arrangement.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Total number of shares issued during the period, including shares forfeited, as a result of Restricted Stock Awards.

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Per share amount of par value or stated value of stock classified as temporary equity. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable.

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Fair value portion of warrants not settleable in cash classified as equity.

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Stock-based Compensation - Additional information (Details) - USD ($)			9 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2015	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Mar. 20, 2020	Jun. 24, 2019	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options grants in period			921,721		366,988
Share based compensation expense			$ 4,710,000	$ 1,856,000	$ 2,702,000	$ 2,062,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value					$ 9.21	$ 0
Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Total Fair Value					$ 239,000
Volvo Stock Purchase Warrant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of warrants							$ 43.3039
Fair value of warrants			$ 2,900,000
Series A Redeemable Convertible Preferred Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Temporary equity par or stated value per share			$ 0.00001		$ 0.00001	$ 0.00001		$ 0.00001
Series A Redeemable Convertible Preferred Stock [Member] \| Volvo Stock Purchase Warrant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of warrants sold							300,000
Temporary equity par or stated value per share							$ 0.00001
Share-based Payment Arrangement, Nonemployee [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation by share based payment arrangements equity instruments other than options non vested number			624		1,999	17,218			37,989
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation by share based payment arrangements equity instruments other than options non vested number			160,925		458,257	1,676,273			3,534,436
Proceeds from restricted stock					$ 61,000,000
Tax benefit in respect of restricted stock issued					0
Restricted Stock [Member] \| Tax Benefit From Restricted Stock Issue [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Tax benefit in respect of restricted stock issued					$ 0
2015 Stock Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based payment award number of shares authorized			3,083,105		2,583,105
2015 Stock Plan [Member] \| Chief Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period shares restricted stock award		6,519,750
2015 Stock Plan [Member] \| Other Individuals [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period shares restricted stock award		960,000
2015 Stock Plan [Member] \| Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	4 years				4 years
Share based compensation expense			$ 2,400,000	1,800,000	$ 2,400,000	$ 1,700,000
Unrecognized stock-based compensation expense period for recognition			1 year 5 months 26 days		1 year 8 months 23 days
Restricted Stock Vested In Period Total Fair Value			$ 1,600,000	2,000,000	$ 2,500,000
Unrecognized stock-based compensation expense other than stock option			$ 2,200,000		$ 3,700,000
2015 Stock Plan [Member] \| Restricted Stock [Member] \| Share-based Payment Arrangement, Nonemployee [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation expense period for recognition			1 year 4 months 6 days		1 year 7 months 2 days
Unrecognized stock-based compensation expense other than stock option			$ 9,623,000,000		$ 44,000	$ 320,000
2015 Stock Plan [Member] \| Restricted Stock [Member] \| Chief Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period shares restricted stock award		6,519,750
Share based compensation by share based payment arrangements equity instruments other than options non vested number						814,969
2015 Stock Plan [Member] \| Restricted Stock [Member] \| Other Individuals [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period shares restricted stock award		960,000
Share based compensation by share based payment arrangements equity instruments other than options non vested number						125,000
2015 Stock Plan [Member] \| Restricted Stock [Member] \| Share-based Payment Arrangement, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage	25.00%	25.00%			25.00%
2015 Stock Plan [Member] \| Restricted Stock [Member] \| Share-based Payment Arrangement, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	36 months	36 months			36 months
Award vesting rights percentage	75.00%	75.00%			75.00%
2015 Stock Plan [Member] \| Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			4 years		4 years
Award expiration period			10 years		10 years
Options grants in period			921,721
Share based compensation expense			$ 2,200,000	$ 50,000.00	$ 240,000
Unrecognized stock-based compensation expense stock option			$ 12,500,000		$ 3,200,000
Unrecognized stock-based compensation expense period for recognition			2 years 1 month 17 days		2 years 7 months 2 days
2015 Stock Plan [Member] \| Employee Stock Option [Member] \| Share-based Payment Arrangement, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage			25.00%		25.00%
2015 Stock Plan [Member] \| Employee Stock Option [Member] \| Share-based Payment Arrangement, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			36 months		36 months
Award vesting rights percentage			75.00%		75.00%