Number of shares available for sale under employee stock purchase plan.

No definition available.

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Period Type:	duration

- Definition

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

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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- Definition

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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Period Type:	duration

- Definition

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

+ References

+ Details

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Period Type:	instant

- Definition

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

+ References

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- Definition

Amount of noncash expense for share-based payment arrangement.

+ References

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-Publisher FASB
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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

+ Details

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- Definition

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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- Definition

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.

+ References

No definition available.

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- Definition

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

+ References

No definition available.

+ Details

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- Definition

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

+ References

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Period Type:	instant

- Definition

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

+ References

+ Details

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- Definition

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

+ References

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- Definition

Maximum number of shares that may be issued in accordance with the plan as a proportion of outstanding capital stock.

+ References

No definition available.

+ Details

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- Definition

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.

+ References

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- Definition

Number of share options (or share units) exercised during the current period.

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Stock-Based Compensation - Additional Information (Details) - USD ($)			1 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended
	Nov. 29, 2017	Oct. 11, 2017	Dec. 31, 2019	May 31, 2018	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Recognized stock-based compensation expense							$ 1,734,000	$ 1,607,000
Number Of Shares Available For Sale Under Employee Stock Purchase Plan					0
Employees And Non Employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expense related to options granted					$ 759,000	$ 943,000	$ 1,734,000	1,607,000
Options Issued and Outstanding
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of options exercised							0
Options Issued and Outstanding \| Directors
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Option granted							86,484
Grant date fair value							$ 1.80
Options Issued and Outstanding \| Employees And Non Employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Option granted							0
Options Issued and Outstanding \| Employees and Directors
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expense related to options granted					700,000	900,000	$ 1,600,000	1,500,000
Unrecognized compensation expense					5,900,000		$ 5,900,000
Unrecognized compensation expense, estimated weighted-average period for recognition							2 years 4 months 9 days
Options Issued and Outstanding \| Non-employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expense related to options granted					7,000	$ 40,000	$ 8,000	$ 48,000
Unrecognized compensation expense					28,000		$ 28,000
Unrecognized compensation expense, estimated weighted-average period for recognition							1 year 8 months 26 days
Restricted stock units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation expense, estimated weighted-average period for recognition							3 years 5 months 8 days
Recognized stock-based compensation expense					52,000		$ 100,000
Unrecognized stock-based compensation expense					$ 700,000		$ 700,000
Restricted stock units \| Non-employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares granted					0	0	0	0
Restricted stock units \| Employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares granted			813,335	24,960	0	0	0	0
Grant date fair value			$ 1.27	$ 9.03
2017 Stock Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares reserved for issuance	630,662	537,914			537,914		537,914
Number of additional shares reserved for issuance	1,866,009	630,662
2017 Stock Incentive Plan \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Terms of stock based options granted							10 years
2018 Stock Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of additional shares added on outstanding shares							4.00%
2018 Stock Incentive Plan \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares reserved for issuance					3,322,473		3,322,473
2018 Stock Incentive Plan \| Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares reserved for issuance					2,200,260		2,200,260
2018 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares reserved for issuance										275,030
Percentage of additional shares added on outstanding shares										1.00%
Number Of Shares Available For Sale Under Employee Stock Purchase Plan							0
2018 Employee Stock Purchase Plan \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of additional shares reserved for issuance							920,030		555,583
2018 Employee Stock Purchase Plan \| Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of additional shares reserved for issuance							543,926