Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	August 2019 ATM Facility [Member] Preferred Stock [Member] Series A Preferred Stock [Member]	August 2019 ATM Facility [Member] Preferred Stock [Member] Series B Preferred Stock [Member]	August 2019 ATM Facility [Member] Common Stock [Member]	August 2019 ATM Facility [Member] Additional Paid-in Capital [Member]	August 2019 ATM Facility [Member] Retained Earnings [Member]	August 2019 ATM Facility [Member]	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]	Purchase Agreement with LPC [Member] Preferred Stock [Member] Series A Preferred Stock [Member]	Purchase Agreement with LPC [Member] Preferred Stock [Member] Series B Preferred Stock [Member]	Purchase Agreement with LPC [Member] Common Stock [Member]	Purchase Agreement with LPC [Member] Additional Paid-in Capital [Member]	Purchase Agreement with LPC [Member] Retained Earnings [Member]	Purchase Agreement with LPC [Member]	Conversion of Series A Convertible Preferred Stock into Common Stock [Member] Preferred Stock [Member] Series A Preferred Stock [Member]	Conversion of Series A Convertible Preferred Stock into Common Stock [Member] Preferred Stock [Member] Series B Preferred Stock [Member]	Conversion of Series A Convertible Preferred Stock into Common Stock [Member] Common Stock [Member]	Conversion of Series A Convertible Preferred Stock into Common Stock [Member] Additional Paid-in Capital [Member]	Conversion of Series A Convertible Preferred Stock into Common Stock [Member] Retained Earnings [Member]	Conversion of Series A Convertible Preferred Stock into Common Stock [Member]	Conversion of Debt into Series B Convertible Preferred Stock and Common Stock [Member] Preferred Stock [Member] Series A Preferred Stock [Member]	Conversion of Debt into Series B Convertible Preferred Stock and Common Stock [Member] Preferred Stock [Member] Series B Preferred Stock [Member]	Conversion of Debt into Series B Convertible Preferred Stock and Common Stock [Member] Common Stock [Member]	Conversion of Debt into Series B Convertible Preferred Stock and Common Stock [Member] Additional Paid-in Capital [Member]	Conversion of Debt into Series B Convertible Preferred Stock and Common Stock [Member] Retained Earnings [Member]	Conversion of Debt into Series B Convertible Preferred Stock and Common Stock [Member]	Series A and Series B Warrants [Member] Preferred Stock [Member] Series A Preferred Stock [Member]	Series A and Series B Warrants [Member] Preferred Stock [Member] Series B Preferred Stock [Member]	Series A and Series B Warrants [Member] Common Stock [Member]	Series A and Series B Warrants [Member] Additional Paid-in Capital [Member]	Series A and Series B Warrants [Member] Retained Earnings [Member]	Series A and Series B Warrants [Member]	Series A-2 and Series B-2 Warrants [Member] Preferred Stock [Member] Series A Preferred Stock [Member]	Series A-2 and Series B-2 Warrants [Member] Preferred Stock [Member] Series B Preferred Stock [Member]	Series A-2 and Series B-2 Warrants [Member] Common Stock [Member]	Series A-2 and Series B-2 Warrants [Member] Additional Paid-in Capital [Member]	Series A-2 and Series B-2 Warrants [Member] Retained Earnings [Member]	Series A-2 and Series B-2 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																																													46,363
Balances at Dec. 31, 2018																																														$ 160,297	$ (155,385)		$ 4,912
Stock offering, net of issuance costs (in shares)			100,418			100,423	547,342		194,595
Stock offering, net of issuance costs				$ 6,322		$ 6,322				$ 9,952		$ 9,952
Conversion of stock (in shares)																			(362,124)		362,124					31,300
Conversion of stock																												$ 35,413		$ 35,413
Series B convertible preferred stock dividends																																														(380)			(380)
Series B convertible preferred stock dividends paid in PIK shares (in shares)																																												378				378
Series B convertible preferred stock dividends paid in PIK shares																																														378			378
Stock-based compensation expense																																														2,251			2,251
Issuance of restricted common shares in connection with consulting agreement (in shares)																																													3,869
Issuance of restricted common shares in connection with consulting agreement																																														75			75
Issuance of common shares from employee stock purchase plan (in shares)																																													154
Issuance of common shares from employee stock purchase plan																																														56			56
Issuance of restricted stock awards to directors, employees and consultants (in shares)																																													118
Issuance of restricted stock awards to directors, employees and consultants																																														74			74
Reverse stock split - cancellation and payout of fractional shares (in shares)																																													(70)
Reverse stock split - cancellation and payout of fractional shares																																														(6)			(6)
Net loss																																															(42,526)		(42,526)
Balances (in shares) at Dec. 31, 2019																																											185,218	31,678	707,571
Balances at Dec. 31, 2019																																														214,432	(197,911)		16,521
Balances (in shares) at Dec. 31, 2018																																													46,363
Balances at Dec. 31, 2018																																														160,297	(155,385)		4,912
Series B convertible preferred stock dividends paid in PIK shares (in shares)																																																4,519
Balances (in shares) at Dec. 31, 2020																																												35,819	2,171,316
Balances at Dec. 31, 2020																																														226,800	(219,826)		6,974
Balances (in shares) at Dec. 31, 2019																																											185,218	31,678	707,571
Balances at Dec. 31, 2019																																														214,432	(197,911)		16,521
Stock offering, net of issuance costs (in shares)																																													52,500
Stock offering, net of issuance costs																																														341			341
Conversion of stock (in shares)																																											(185,218)		185,218
Conversion of stock
Series B convertible preferred stock dividends																																														(4,149)			(4,149)
Series B convertible preferred stock dividends paid in PIK shares (in shares)																																												4,141				4,141
Series B convertible preferred stock dividends paid in PIK shares																																														4,141			4,141
Stock-based compensation expense																																														2,577			2,577
Issuance of restricted common shares in connection with consulting agreement (in shares)																																													10,995
Issuance of restricted common shares in connection with consulting agreement																																														74			74
Issuance of common shares from employee stock purchase plan (in shares)																																													84
Issuance of common shares from employee stock purchase plan
Issuance of restricted stock awards to directors, employees and consultants (in shares)																																													25
Net loss																																															(21,915)		(21,915)
Issuance costs										$ (33)		$ (33)				$ (494)		$ (494)
Issuance of common shares in connection with warrant exercises (in shares)																																	1,115,863						93,129
Issuance of common shares in connection with warrant exercises																																		$ 7,814		$ 7,814				$ 593		$ 593
Modification of Series A and B warrants in connection with 2020 Warrant Offering																																		$ 1,838		$ 1,838
Issuance of Series A-2 and B-2 warrants in connection with 2020 Warrant Offering																																														1,838			1,838
Transaction costs in connection with warrant offering																																								$ (1,838)		$ (1,838)
Transaction costs in connection with warrant offering																																														(334)			(334)
Restricted stock awards
Reverse stock split - rounding adjustment (in shares)																																													5,931
Balances (in shares) at Dec. 31, 2020																																												35,819	2,171,316
Balances at Dec. 31, 2020																																														$ 226,800	$ (219,826)		$ 6,974