Aggregate number of common shares reserved for future issuance.

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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.

+ References

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

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- Definition

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.

+ References

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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 additional shares authorized for issuance under share-based payment arrangement.

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No definition available.

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

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- Definition

Number of options outstanding, including both vested and non-vested options.

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Stock Option Plans (Details) - USD ($) $ in Thousands	3 Months Ended
Stock Option Plans (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019	Feb. 12, 2020	Feb. 11, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance (in shares)	5,065,641
Options outstanding under The 2020 Plan (in shares)	2,458,091	2,371,545	2,461,923		2,473,130	2,377,180
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance (in shares)	5,050,000
Options authorized (in shares)	1,029,588
Unrecognized stock-based compensation	$ 339	$ 703
Estimated weighted average amortization period (in years)	1 year	1 year 6 months
The 2020 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance (in shares)	2,591,909
Options outstanding under The 2020 Plan (in shares)	0
Equity Awards outstanding under The 2020 Plan (in shares)	0
Number of shares authorized by 2020 plan (in shares)	5,050,000
The 2020 Equity Incentive Plan \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options authorized (in shares)	2,461,923
Transphorm Technology 2007 Stock Plan and 2015 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding under The 2020 Plan (in shares)				29,703,285
Number of shares authorized by 2020 plan (in shares)	2,588,077