Condensed Consolidated Statements of Stockholders' Equity (Deficit) (Unaudited) - USD ($) $ in Thousands	November 2019 Offering [Member] Preferred Stock [Member] Series A Preferred Stock [Member]	November 2019 Offering [Member] Preferred Stock [Member] Series B Preferred Stock [Member]	November 2019 Offering [Member] Common Stock [Member]	November 2019 Offering [Member] Additional Paid-in Capital [Member]	November 2019 Offering [Member] Retained Earnings [Member]	November 2019 Offering [Member]	Series A Warrants [Member] Preferred Stock [Member] Series A Preferred Stock [Member]	Series A Warrants [Member] Preferred Stock [Member] Series B Preferred Stock [Member]	Series A Warrants [Member] Common Stock [Member]	Series A Warrants [Member] Additional Paid-in Capital [Member]	Series A Warrants [Member] Retained Earnings [Member]	Series A Warrants [Member]	Series B Warrants [Member] Preferred Stock [Member] Series A Preferred Stock [Member]	Series B Warrants [Member] Preferred Stock [Member] Series B Preferred Stock [Member]	Series B Warrants [Member] Common Stock [Member]	Series B Warrants [Member] Additional Paid-in Capital [Member]	Series B Warrants [Member] Retained Earnings [Member]	Series B Warrants [Member]	Preferred Stock [Member] Series A Preferred Stock [Member]	Preferred Stock [Member] Series B Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Series B Preferred Stock [Member]	Total
Balances (in shares) at Dec. 31, 2018																					463,630
Balances at Dec. 31, 2018																						$ 160,297	$ (155,385)		$ 4,912
Stock-based compensation expense																						470			470
Issuance of common shares from employee stock purchase plan (in shares)																					429
Issuance of common shares from employee stock purchase plan																						35			35
Issuance of restricted shares (in shares)																					6
Issuance of restricted shares																						1			1
Net loss																							(10,029)		(10,029)
Issuance of restricted common shares in connection with consulting agreement (in shares)																					274
Issuance of restricted common shares in connection with consulting agreement																						25			25
Balances (in shares) at Mar. 31, 2019																					464,339
Balances at Mar. 31, 2019																						160,828	(165,414)		(4,586)
Balances (in shares) at Dec. 31, 2018																					463,630
Balances at Dec. 31, 2018																						160,297	(155,385)		4,912
Series B convertible preferred stock dividends (in shares)																								378
Balances (in shares) at Dec. 31, 2019																			1,852,173	31,678	7,075,684
Balances at Dec. 31, 2019																					$ 1	214,431	(197,911)		16,521	[1]
Issuance costs in connection with November 2019 Offering				$ (30)		$ (30)
Conversion of Series A convertible preferred stock into common stock (in shares)																			(1,852,173)
Conversion of Series A convertible preferred stock into common stock
Conversion of Series A convertible preferred stock into common stock (in shares)																					1,852,173
Issuance of common shares in connection with warrant exercises (in shares)									1,026,240						45,473
Issuance of common shares in connection with warrant exercises										$ 1,591		$ 1,591				$ 70		$ 70
Series B convertible preferred stock dividends (in shares)																				989				989
Series B convertible preferred stock dividends																						(1)			(1)
Stock-based compensation expense																						686			686
Issuance of common shares from employee stock purchase plan (in shares)																					320
Issuance of common shares from employee stock purchase plan
Issuance of restricted shares (in shares)																					28,313
Issuance of restricted shares																						24			24
Net loss																							(6,310)		(6,310)
Balances (in shares) at Mar. 31, 2020																				32,667	10,028,203
Balances at Mar. 31, 2020																					$ 1	$ 216,771	$ (204,221)		$ 12,551

[1] The condensed consolidated balance sheet as of December 31, 2019 has been derived from the audited consolidated financial statements as of that date.