Quarterly report pursuant to Section 13 or 15(d)

Capital Structure - Narrative (Details)

Capital Structure - Narrative (Details) $ / shares in Units, $ in Millions									1 Months Ended				3 Months Ended				9 Months Ended
	Sep. 17, 2021 USD ($) shares	Jun. 04, 2021 USD ($) $ / shares shares	Jun. 11, 2020 USD ($) shares	Mar. 17, 2020 USD ($) shares	Feb. 06, 2020 USD ($) shares	Feb. 03, 2020 shares	Dec. 27, 2018	Dec. 26, 2018 shares	Aug. 31, 2021 USD ($) shares	Jul. 31, 2021 USD ($)	Apr. 30, 2021 shares	Jan. 31, 2021 USD ($) $ / shares shares	Sep. 30, 2021 class_of_stock $ / shares shares	Jun. 30, 2021 $ / shares shares	Mar. 31, 2021 USD ($) shares	Mar. 31, 2020 shares	Sep. 30, 2021 class_of_stock $ / shares shares	Sep. 30, 2020 shares	Dec. 31, 2020 $ / shares shares
Common Stock
Number of classes of stock authorized to issue \| class_of_stock													2				2
Number of shares of capital stock authorized to issue (in shares)													205,000,000				205,000,000
Common stock, shares authorized (in shares)													200,000,000				200,000,000		200,000,000
Preferred stock, shares authorized (in shares)													5,000,000				5,000,000		5,000,000
Common stock, par value (in dollars per share) \| $ / shares													$ 0.001				$ 0.001		$ 0.001
Preferred stock, par value per share (in dollars per share) \| $ / shares													$ 0.001				$ 0.001		$ 0.001
Sale of stock (in shares)															13,971,889
Exercise price per share (in dollars per share) \| $ / shares												$ 0.001
Percent ownership threshold												9.99%
Proceeds from issuance of warrants \| $												$ 4.4
Preferred stock conversion ratio													0.20				0.20
Preferred stock, shares outstanding (in shares)													0				0		1,257,143
Preferred Stock
Common Stock
Conversion to common stock (in shares)																	(1,257,143)	(1,600,000)
Preferred Stock \| Series B Preferred Stock
Common Stock
Preferred stock conversion ratio							0.20	0.20									0.20
Shares converted (in shares)											1,257,143					1,600,000	1,257,143
Preferred stock, shares outstanding (in shares)													0				0
Common Stock
Common Stock
Conversion to common stock (in shares)											6,285,715					8,000,000	6,285,715	8,000,000
Aevi
Common Stock
Shares issued (in shares)						3,900,000										3,900,000
Nantahala Capital Management LLC
Common Stock
Percentage of ownership	5.00%
Warrant
Common Stock
Sale of stock (in shares)												1,676,923			1,676,923
Horizon & Powerscourt Notes \| Notes Payable
Common Stock
Proceeds from issuance of warrants \| $		$ 0.9
Horizon & Powerscourt Notes \| Notes Payable \| Warrant
Common Stock
Sale of stock (in shares)		403,844												403,844
Exercise price per share (in dollars per share) \| $ / shares		$ 2.60												$ 2.60
Warrants or rights exercisable term		10 years												10 years
Nantahala
Common Stock
Number of shares available under warrant (in shares)												1,676,923	1,676,923				1,676,923
Underwritten Public Offering
Common Stock
Sale of stock (in shares)	14,308,878		15,180,000									13,971,889
Net proceeds \| $	$ 29.0		$ 35.4									$ 37.7			$ 37.7
Underwritten Public Offering \| Armistice
Common Stock
Sale of stock (in shares)	5,454,545		2,000,000									2,500,000
Underwritten Public Offering \| Nantahala
Common Stock
Sale of stock (in shares)												1,400,000
Purchase price (in dollars per share) \| $ / shares												$ 2.599
Underwritten Public Offering \| Officers
Common Stock
Sale of stock (in shares)			110,000
ATM Agreement
Common Stock
Sale of stock (in shares)									2,000,000
Net proceeds \| $									$ 5.3	$ 50.0
Armistice Purchase Agreement
Common Stock
Sale of stock (in shares)				1,951,219
Net proceeds \| $				$ 3.9
Registered Direct Offering
Common Stock
Sale of stock (in shares)					1,306,282
Net proceeds \| $					$ 5.1
Registered Direct Offering \| Armistice
Common Stock
Sale of stock (in shares)					1,256,282
Private Placement \| Preferred Stock \| Series B Preferred Stock
Common Stock
Preferred stock, shares authorized (in shares)								2,857,143