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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644

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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 warrants or rights outstanding.

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+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (e)(2)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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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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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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Per share decrease in exercise price of warrant. Excludes change due to standard antidilution provision.

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Warrants - Additional Information (Detail) - $ / shares		9 Months Ended
Warrants - Additional Information (Detail) - $ / shares	Feb. 08, 2019	Sep. 30, 2020	Jan. 31, 2020	Dec. 31, 2017
Roth 2017 Warrants [Member]
Class Of Warrant Or Right [Line Items]
Warrants to purchase common stock				160,041
Warrants outstanding		21,361	118,696
Common stock warrants, exercise price per share		$ 88.50
February 2019 Warrants [Member]
Class Of Warrant Or Right [Line Items]
Warrants are fully vested, exercise price	$ 52.50
February 2019 Warrants [Member] \| IPO Selling Agent [Member]
Class Of Warrant Or Right [Line Items]
Purchase of warrant issued	12,113
February 2019 Warrants [Member] \| IPO [Member]
Class Of Warrant Or Right [Line Items]
Warrants years of life	4 years
February 2019 Offering [Member] \| Roth 2017 Warrants [Member]
Class Of Warrant Or Right [Line Items]
Warrants outstanding		118,696
Exercise price of warrants		$ 42.00
February 2020 Offering [Member] \| Roth 2017 Warrants [Member]
Class Of Warrant Or Right [Line Items]
Warrants outstanding		118,696
Exercise price of warrants		$ 0.0001