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		12 Months Ended
	Jun. 11, 2020 USD ($) shares	Mar. 17, 2020 USD ($) shares	Feb. 06, 2020 USD ($) shares	Feb. 03, 2020 shares	Dec. 27, 2018 $ / shares shares	Dec. 26, 2018 shares	Apr. 30, 2021 shares	Jan. 31, 2021 USD ($) $ / shares shares	Dec. 31, 2018 $ / shares shares	Mar. 31, 2021 USD ($) class_of_stock $ / shares shares	Mar. 31, 2020 shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2020 $ / shares shares
Common Stock
Number of classes of stock authorized to issue \| class_of_stock										2
Number of shares of capital stock authorized to issue (in shares)										205,000,000
Common stock, shares authorized (in shares)										200,000,000			200,000,000
Preferred stock, shares authorized (in shares)										5,000,000			5,000,000
Common stock, par value (in dollars per share) \| $ / shares										$ 0.001			$ 0.001
Preferred stock, par value per share (in dollars per share) \| $ / shares										$ 0.001			$ 0.001
Sale of stock (in shares)								13,971,889
Number of shares available under warrant (in shares)									4,000,000			4,000,000
Exercise price per share (in dollars per share) \| $ / shares								$ 0.001	$ 12.50			$ 12.50
Percent ownership threshold										9.99%
Issuance of warrant, component of additional paid-in capital \| $										$ 4.4
Proceeds from warrant exercises \| $												$ 5.7
Warrants outstanding term									5 years 6 months			5 years 6 months
Aevi
Common Stock
Shares issued (in shares)				3,900,000							3,900,000
Common Stock
Common Stock
Conversion to common stock (in shares)										6,285,715	8,000,000	14,285,715
Common Stock \| Subsequent Event
Common Stock
Conversion to common stock (in shares)							6,285,715
Preferred Stock
Common Stock
Conversion to common stock (in shares)											(1,600,000)
Preferred Stock \| Series B Preferred Stock
Common Stock
Preferred stock, shares authorized (in shares)					2,857,143
Preferred stock conversion ratio					0.20	0.20			0.20	0.20
Shares converted (in shares)										1,257,143	1,600,000
Preferred Stock \| Series B Preferred Stock \| Subsequent Event
Common Stock
Shares converted (in shares)							1,257,143
Nantahala Capital Management LLC
Common Stock
Percentage of ownership								5.00%
Nantahala
Common Stock
Number of shares available under warrant (in shares)								1,676,923
Warrant
Common Stock
Sale of stock (in shares)								1,676,923
Underwritten Public Offering
Common Stock
Sale of stock (in shares)	15,180,000							13,971,889
Net proceeds \| $	$ 35.4							$ 37.7
Underwritten Public Offering \| Armistice
Common Stock
Sale of stock (in shares)	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
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
Common Stock
Number of shares available under warrant (in shares)					14,285,714
Exercise price per share (in dollars per share) \| $ / shares					$ 0.40
Private Placement \| Preferred Stock \| Series B Preferred Stock
Common Stock
Preferred stock, shares authorized (in shares)					2,857,143	2,857,143
Preferred stock, par value per share (in dollars per share) \| $ / shares					$ 2.00