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Stockholders' Equity - Common stock (Details) - USD ($)				3 Months Ended		9 Months Ended	12 Months Ended
	Oct. 23, 2020	Sep. 30, 2020	Jun. 16, 2020	Mar. 31, 2021	Mar. 31, 2020	Sep. 30, 2020	Dec. 31, 2020
Class of Stock [Line Items]
Sale of common stock, net				$ 7,078,000
Proceeds from sale of common stock, net				7,180,000	$ 0
Common Stock [Member]
Class of Stock [Line Items]
Sale of common stock, net				$ 2,000
Common stock issued (in shares)				2,534,879,000
Lincoln Park Capital Fund, LLC [Member] | 2020 Repurchase Agreement [Member] | Common Stock [Member]
Class of Stock [Line Items]
Sale of common stock, net		$ 25,000,000				$ 25,000,000
Common stock issued (in shares)				1,397,686			353,113
Period exercisable from the date of issuance		36 months				36 months
Closing price per share			$ 1.05
Proceeds from sale of common stock, net				$ 3,900,000			$ 700,000
Lincoln Park Capital Fund, LLC [Member] | 2020 Repurchase Agreement [Member] | Common Stock [Member] | Commitment Fee
Class of Stock [Line Items]
Common stock issued (in shares)							180,701
Lincoln Park Capital Fund, LLC [Member] | 2020 Repurchase Agreement [Member] | Common Stock [Member] | Minimum [Member]
Class of Stock [Line Items]
Percentage issuance of common stock			19.99%
Lincoln Park Capital Fund, LLC [Member] | 2020 Repurchase Agreement [Member] | Common Stock [Member] | Minimum [Member] | Single Regular Purchase [Member]
Class of Stock [Line Items]
Sale of common stock, net		$ 500,000
Common stock issued (in shares)		50,000
Lincoln Park Capital Fund, LLC [Member] | 2020 Repurchase Agreement [Member] | Common Stock [Member] | Maximum [Member]
Class of Stock [Line Items]
Common stock issued (in shares)			23,800,000
Lincoln Park Capital Fund, LLC [Member] | 2020 Repurchase Agreement [Member] | Common Stock [Member] | Maximum [Member] | Single Regular Purchase [Member]
Class of Stock [Line Items]
Common stock issued (in shares)		100,000
Closing price per share		$ 0.25				$ 0.25
Canaccord Genuity LLC [Member] | Common Stock [Member]
Class of Stock [Line Items]
Common stock issued (in shares)				1,137,193			1,616,331
Proceeds from sale of common stock, net	$ 10,000,000			$ 3,200,000			$ 3,200,000
Remaining availability under financing facility	0
Canaccord Genuity LLC [Member] | Sales Agreement | Common Stock [Member] | At The Market Offering Program
Class of Stock [Line Items]
Remaining availability under financing facility	$ 0

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