Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity - Additional information (Details)

Stockholders' Equity - Additional information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended					12 Months Ended
	Oct. 31, 2019	Aug. 31, 2019	Apr. 30, 2019	Sep. 30, 2018	Sep. 20, 2018	Dec. 31, 2019	Dec. 31, 2018	Nov. 09, 2018
Class of Warrant or Right [Line Items]
Issuance of common stock, net						$ 8,237	$ 2,437
Conversion of Stock, Shares Issued							5,483,334
Class of Warrant or Right, Outstanding						48,618,000
Warrants, Expiration Period					5 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross						854,000
Sale of Stock, Price Per Share				$ 1.44
Proceeds from Warrant Exercises				$ 3,300		$ 1,603	$ 3,268
Class A Units [Member]
Class of Warrant or Right [Line Items]
Issuance of common stock, net (in shares)					850,000
Sale of Stock, Price Per Share					$ 1.50
Class B Units [Member]
Class of Warrant or Right [Line Items]
Issuance of common stock, net (in shares)					8,225
Sale of Stock, Price Per Share					$ 1,000
Common Stock [Member]
Class of Warrant or Right [Line Items]
Issuance of common stock, net (in shares)						37,696,000	1,815,000
Issuance of common stock, net						$ 37	$ 2
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross				950,000
Representatives Purchase Warrant [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights				253,334
Class of Warrant or Right, Exercise Price of Warrants or Rights				$ 1.68
Warrant
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights					950,000			2,178,484
Class of Warrant or Right, Exercise Price of Warrants or Rights				$ 0.06
Warrant \| Class B Units [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights					667
August 2019 Offering \| Common Stock [Member]
Class of Warrant or Right [Line Items]
Issuance of common stock, net (in shares)		1,480,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights		2,852,314
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 1.07
August 2019 Offering \| Pre-Funded Warrants [Member] \| Common Stock [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights		1,372,314
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 0.01
August 2019 Offering \| Placement Warrants [Member] \| Common Stock [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights		2,852,314
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 1.07
October 2019 Offering
Class of Warrant or Right [Line Items]
Issuance of common stock, net (in shares)	40,276,000
Shares Issued, Price Per Share	$ 0.225
October 2019 Offering \| Common Stock [Member]
Class of Warrant or Right [Line Items]
Issuance of common stock, net (in shares)	35,886,000
October 2019 Offering \| Pre-Funded Warrants [Member] \| Common Stock [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	4,390,000
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 0.01
October 2019 Offering \| Placement Warrants [Member] \| Class B Units [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	40,276,000
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 0.225
ATM
Class of Warrant or Right [Line Items]
Issuance of common stock, net (in shares)						329,656
Shares Issued, Price Per Share						$ 1.60
Proceeds from Issuance of Common Stock						$ 500
ATM \| Maximum [Member]
Class of Warrant or Right [Line Items]
Issuance of common stock, net		$ 4,000	$ 8,600