Equity distribution agreement maximum value of common shares issuable.

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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 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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Number of warrants or rights outstanding.

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- Definition

The number of shares converted in a noncash (or part noncash) transaction. Noncash is defined as transactions during a period that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

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- Definition

The number of new shares issued in the conversion of stock in a noncash (or part noncash) transaction. Noncash is defined as transactions during a period that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

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Number of shares issued for each share of convertible preferred stock that is converted.

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Aggregate share number for all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by stockholders. Does not include preferred shares that have been repurchased.

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Number of new stock issued during the period.

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Stockholders' Equity - Additional Information (Detail) - USD ($)		6 Months Ended	12 Months Ended
	Dec. 23, 2020	Jun. 30, 2021	Dec. 31, 2020	Mar. 31, 2021
Series X1 Preferred Stock [Member]
Class Of Stock [Line Items]
Warrants available for exercise		55,853.875
Shares of common stock issued upon conversion of each share of preferred stock		55.5556
Series X Preferred Stock [Member]
Class Of Stock [Line Items]
Preferred shares outstanding		6,204	0
Common Stock Warrants [Member]
Class Of Stock [Line Items]
Warrants available for exercise		846,939	337,822
Common Stock [Member]
Class Of Stock [Line Items]
Common stock number of shares issued	1,004,111
Warrant Exchange Agreement and Exchange Agreements [Member] \| Series X Preferred Stock [Member]
Class Of Stock [Line Items]
Preferred shares outstanding			6,203.98
Warrant Exchange Agreement and Exchange Agreements [Member] \| Common Stock [Member] \| Series X Preferred Stock [Member]
Class Of Stock [Line Items]
Shares of common stock issued upon conversion of each share of preferred stock			344,663
Exchange Agreement [Member]
Class Of Stock [Line Items]
Warrants available for exercise		509,117
Jeffries LLC [Member] \| Equity Distribution Agreement [Member]
Class Of Stock [Line Items]
Equity distribution agreement maximum value of common shares issuable				$ 75,000,000.0
Common stock number of shares issued		0
BVF Exchanging Stockholders, Series X Exchanging Stockholders [Member] \| Series X Exchange Agreement [Member] \| Series X Preferred Stock [Member]
Class Of Stock [Line Items]
Conversion of stock, shares issued			6,203.98
BVF Exchanging Stockholders, Series X Exchanging Stockholders [Member] \| Series X Exchange Agreement [Member] \| Common Stock [Member]
Class Of Stock [Line Items]
Conversion of stock, shares converted			344,666
BVF Exchanging Stockholders \| Warrant Exchange Agreement and Exchange Agreements [Member] \| Common Stock [Member]
Class Of Stock [Line Items]
Warrants to issue shares of common stock			509,117