Quarterly report pursuant to Section 13 or 15(d)

Capital Structure - Common Stock (Details)

Capital Structure - Common Stock (Details) $ / shares in Units, $ in Millions								1 Months Ended				3 Months Ended	6 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 ($) shares	Dec. 26, 2018 shares	Jun. 30, 2020 USD ($) class_of_stock $ / shares shares	Mar. 31, 2020 USD ($) shares	Feb. 29, 2020 USD ($) shares	Dec. 31, 2018 $ / shares shares	Mar. 31, 2020 shares	Jun. 30, 2020 class_of_stock Vote $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2019 $ / shares shares	Dec. 27, 2018 $ / shares shares	Dec. 31, 2014 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)	15,180,000							15,180,000
Net proceeds \| $	$ 35.4							$ 35.4
Number of shares available under warrant (in shares)											4,000,000			4,000,000
Exercise price per share (in dollars per share) \| $ / shares											$ 12.50			$ 12.50
Warrants outstanding term											5 years 6 months			5 years 6 months
Preferred Stock
Common Stock
Conversion of preferred stock to common stock (in shares)													(1,600,000)
Common Stock
Common Stock
Number of shares available under warrant (in shares)																	22,328
Conversion of preferred stock to common stock (in shares)												8,000,000.0	8,000,000
Series B Preferred Stock \| Preferred Stock
Common Stock
Preferred stock conversion ratio							0.20				0.20		0.20
Number of shares available under warrant (in shares)																	625,208
Shares converted (in shares)												1,600,000
Common Stock
Common Stock
Number of votes per share \| Vote													1
Number of preemptive, conversion or subscription rights \| class_of_stock													0
Number of redemption or sinking fund provisions \| class_of_stock													0
Underwritten Public Offering
Common Stock
Sale of stock (in shares)	15,180,000
Net proceeds \| $	$ 35.4
Over-Allotment Option
Common Stock
Sale of stock (in shares)	1,980,000							1,980,000
Armistice Purchase Agreement
Common Stock
Sale of stock (in shares)		1,951,219			1,200,000				1,951,219
Net proceeds \| $		$ 3.9			$ 3.7				$ 3.9
Registered Direct Offering
Common Stock
Sale of stock (in shares)			1,306,282							1,306,282
Net proceeds \| $			$ 5.1
Bought Deal
Common Stock
Sale of stock (in shares)						1,818,182
Net proceeds \| $						$ 9.0
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
Proceeds from warrant exercises \| $														$ 5.7
Private Placement \| Series B Preferred Stock \| Preferred Stock
Common Stock
Preferred stock, shares authorized (in shares)							2,857,143				2,857,143			2,857,143		2,857,143
Preferred stock, par value per share (in dollars per share) \| $ / shares																$ 2.00
Armistice \| Underwritten Public Offering
Common Stock
Sale of stock (in shares)	2,000,000
Armistice \| Registered Direct Offering
Common Stock
Sale of stock (in shares)			1,256,282
Armistice \| Registered Direct Offering \| Common Stock
Common Stock
Net proceeds \| $										$ 5.1
Armistice \| Bought Deal
Common Stock
Sale of stock (in shares)						363,637
Officers
Common Stock
Sale of stock (in shares)	110,000
Aevi
Common Stock
Shares issued (in shares)				3,900,000