Stock Based Compensation - Stock Options (Details) - $ / shares	1 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended
May 31, 2020	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2019
The activity related to stock option grants to employees and nonemployees
Outstanding at beginning (in shares)			2,498,606
Granted (in shares)	840,450		1,824,375
Exercised (in shares)		0	(1,449)
Forfeited (in shares)			(567,356)
Outstanding at end (in shares)		3,754,176	3,754,176	2,498,606
Vested and exercisable at end (in shares)		1,358,519	1,358,519
Vested and expected to vest at end (in shares)		3,754,176	3,754,176
Weighted average exercise price per share
Outstanding at beginning (in dollars per share)			$ 17.18
Granted (in dollars per share)			4.77
Exercised (in dollars per share)			1.08
Forfeited (in dollars per share)			13.81
Outstanding at end (in dollars per share)		$ 11.67	11.67	$ 17.18
Vested and exercisable at end (in dollars per share)		20.83	20.83
Vested and expected to vest at end (in dollars per share)		$ 11.67	$ 11.67
Weighted-average remaining contractual life (years)
Outstanding (in years)			8 years	7 years 8 months 12 days
Vested and exercisable at end (in years)			6 years
Vested and expected to vest at end (in years)			8 years

No definition available.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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

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

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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- Definition

Number of fully vested and expected to vest exercisable options that may be converted into shares under option plan. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Weighted-average exercise price, at which grantee can acquire shares reserved for issuance, for fully vested and expected to vest exercisable or convertible options. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Number of fully vested and expected to vest options outstanding that can be converted into shares under option plan. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Weighted-average exercise price, at which grantee can acquire shares reserved for issuance, for fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average remaining contractual term for fully vested and expected to vest exercisable or convertible options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Weighted average remaining contractual term for fully vested and expected to vest options outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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

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