Annual report pursuant to Section 13 and 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 ($) shares	Feb. 03, 2020 shares	Sep. 04, 2019 USD ($) shares	Mar. 08, 2019 USD ($) shares	Dec. 27, 2018 $ / shares shares	Dec. 26, 2018 $ / shares shares	Jan. 31, 2021 USD ($) $ / shares shares	Apr. 30, 2020 USD ($)	Mar. 31, 2020 shares	Dec. 31, 2020 class_of_stock $ / shares shares	Dec. 31, 2020 class_of_stock $ / shares shares	Dec. 31, 2020 USD ($) class_of_stock $ / shares shares	Dec. 31, 2020 class_of_stock $ / shares shares	Dec. 31, 2020 vote class_of_stock $ / shares shares	Dec. 31, 2020 product class_of_stock $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2019 $ / shares shares
Class of Stock [Line Items]
Number of classes of stock authorized to issue \| class_of_stock												2	2	2	2	2	2
Number of shares of capital stock authorized to issue (in shares)												205,000,000	205,000,000	205,000,000	205,000,000	205,000,000	205,000,000
Common stock, shares authorized (in shares)												200,000,000	200,000,000	200,000,000	200,000,000	200,000,000	200,000,000		200,000,000
Preferred stock, shares authorized (in shares)											2,900,000	5,000,000	5,000,000	5,000,000	5,000,000	5,000,000	5,000,000		5,000,000
Common stock, par value (in dollars per share) \| $ / shares												$ 0.001	$ 0.001	$ 0.001	$ 0.001	$ 0.001	$ 0.001		$ 0.001
Preferred stock, par value per share (in dollars per share) \| $ / shares							$ 2.00					$ 0.001	$ 0.001	$ 0.001	$ 0.001	$ 0.001	$ 0.001		$ 0.001
Net proceeds \| $										$ 12.8				$ 44.4				$ 5.7
Number of shares available under warrant (in shares)																		4,000,000
Exercise price per share (in dollars per share) \| $ / shares																		$ 12.50
Expected life																		5 years 6 months
Aevi
Class of Stock [Line Items]
Consideration issued (in shares)				3,900,000
Subsequent Event
Class of Stock [Line Items]
Exercise price per share (in dollars per share) \| $ / shares									$ 0.001
Subsequent Event \| Warrant
Class of Stock [Line Items]
Number of shares issued (in shares)									1,676,923
Subsequent Event \| Nantahala Capital Management LLC
Class of Stock [Line Items]
Percentage of ownership									5.00%
Common stock
Class of Stock [Line Items]
Consideration issued (in shares)													3,893,361
Shares issued upon conversion (in shares)											8,000,000.0
Series B convertible preferred stock \| Preferred Stock
Class of Stock [Line Items]
Preferred stock conversion ratio							0.20	0.20				0.20						0.20
Shares converted (in shares)											1,600,000
Common stock
Class of Stock [Line Items]
Net proceeds \| $										$ 12.8
Number of votes per share \| vote																1
Number of preemptive, conversion or subscription rights															0		0
Number of redemption or sinking fund provisions \| class_of_stock															0
Private Placement
Class of Stock [Line Items]
Number of shares available under warrant (in shares)							14,285,714
Exercise price per share (in dollars per share) \| $ / shares							$ 0.40
Private Placement \| Series B convertible preferred stock \| Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)							2,857,143	2,857,143										2,857,143
Preferred stock, par value per share (in dollars per share) \| $ / shares								$ 0.001
Underwritten Public Offering
Class of Stock [Line Items]
Number of shares issued (in shares)	15,180,000
Net proceeds \| $	$ 35.4
Underwritten Public Offering \| Subsequent Event
Class of Stock [Line Items]
Number of shares issued (in shares)									13,971,889
Net proceeds \| $									$ 37.6
Registered Direct Offering
Class of Stock [Line Items]
Number of shares issued (in shares)			1,306,282
Net proceeds \| $			$ 5.1
Armistice Purchase Agreement
Class of Stock [Line Items]
Number of shares issued (in shares)		1,951,219			1,200,000
Net proceeds \| $		$ 3.9			$ 3.7
Bought Deal
Class of Stock [Line Items]
Number of shares issued (in shares)						1,818,182
Net proceeds \| $						$ 9.0
Nantahala \| Subsequent Event
Class of Stock [Line Items]
Number of shares available under warrant (in shares)									1,676,923
Nantahala \| Underwritten Public Offering \| Subsequent Event
Class of Stock [Line Items]
Number of shares issued (in shares)									1,400,000
Sale of stock price per share (in dollars per share) \| $ / shares									$ 2.599
Armistice \| Series B convertible preferred stock \| Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)							2,857,143
Armistice \| Underwritten Public Offering
Class of Stock [Line Items]
Number of shares issued (in shares)	2,000,000
Armistice \| Underwritten Public Offering \| Subsequent Event
Class of Stock [Line Items]
Number of shares issued (in shares)									2,500,000
Armistice \| Registered Direct Offering
Class of Stock [Line Items]
Number of shares issued (in shares)			1,256,282
Armistice \| Bought Deal
Class of Stock [Line Items]
Number of shares issued (in shares)						363,637
Officers \| Underwritten Public Offering
Class of Stock [Line Items]
Number of shares issued (in shares)	110,000