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Stockholders' Equity - Additional Information (Detail) - USD ($)	3 Months Ended			6 Months Ended
	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2020	Nov. 10, 2020	Jun. 30, 2020	Nov. 08, 2017
Class of Stock [Line Items]
Fair value of warrants				$ 20,176,000		$ 40,483,000
Aggregate value of securities available under shelf registration statement				100,000
Common stock Value Issued	$ 3,136,000	$ 48,451,000	$ 159,000
Unsold Securities Shares and Warrants Under Agreement				107,500,000
Aggregate Value of Securities Available Under Agreement				$ 175,700,000
Warrant [Member]
Class of Stock [Line Items]
Exercise price				$ 2.54
Warrants outstanding				16,061,602
ATM Sales Agreement
Class of Stock [Line Items]
Common stock share issued				958,083
Common stock Value Issued				$ 3,100,000
Two Thousand And Twenty At The Market Sale Agreement
Class of Stock [Line Items]
Aggregate value of securities available under shelf registration statement				60,000,000
Maximum
Class of Stock [Line Items]
Sale of shares and warrants under agreement				200,000,000
Maximum | ATM Sales Agreement
Class of Stock [Line Items]
Sale of shares under agreement							$ 30,000,000
Maximum | Two Thousand And Twenty At The Market Sale Agreement
Class of Stock [Line Items]
Sale of shares under agreement				$ 60,000,000	$ 60,000,000

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