Consolidated Statements of Stockholder's Equity (Unaudited) - USD ($) $ in Thousands	Total	December 2019 Financing [Member]	May 2021 Public Offering [Member]	April 2020 Private Placement [Member]	July 2020 Registered Direct Offering [Member]	August 2020 Public Offering [Member]	LPC [Member]	Common stock [Member]	Common stock [Member] Series B Convertible Preferred Stock [Member]	Common stock [Member] Convertible Preferred Stock [Member]	Common stock [Member] May 2021 Public Offering [Member]	Common stock [Member] April 2020 Private Placement [Member]	Common stock [Member] July 2020 Registered Direct Offering [Member]	Common stock [Member] August 2020 Public Offering [Member]	Preferred stock [Member]	Preferred stock [Member] Series B Convertible Preferred Stock [Member]	Additional paid-in capital [Member]	Additional paid-in capital [Member] Series B Convertible Preferred Stock [Member]	Additional paid-in capital [Member] Convertible Preferred Stock [Member]	Additional paid-in capital [Member] December 2019 Financing [Member]	Additional paid-in capital [Member] May 2021 Public Offering [Member]	Additional paid-in capital [Member] April 2020 Private Placement [Member]	Additional paid-in capital [Member] July 2020 Registered Direct Offering [Member]	Additional paid-in capital [Member] August 2020 Public Offering [Member]	Additional paid-in capital [Member] LPC [Member]	Accumulated other comprehensive income (loss) [Member]	Accumulated deficit [Member]
Beginning Balance at Dec. 31, 2019	$ 18,050							$ 41									$ 63,709									$ 4	$ (45,704)
Beginning Balance, Shares at Dec. 31, 2019								1,474,258							1,121
Stock-based compensation expense	302																302
Costs relating to financing and purchase agreement		$ (34)					$ (13)													$ (34)					$ (13)
Shares issued on conversion of preferred shares									$ 2									$ (2)
Shares issued on conversion of preferred shares, Shares									93,379							(1,121)
Net loss	(3,320)																										(3,320)
Ending Balance at Mar. 31, 2020	14,985							$ 43									63,962									4	(49,024)
Ending Balance, Shares at Mar. 31, 2020								1,567,637
Beginning Balance at Dec. 31, 2019	$ 18,050							$ 41									63,709									4	(45,704)
Beginning Balance, Shares at Dec. 31, 2019								1,474,258							1,121
Restricted stock unit settlements, Shares	236
Net loss	$ (10,006)
Ending Balance at Sep. 30, 2020	25,675							$ 74									81,307									4	(55,710)
Ending Balance, Shares at Sep. 30, 2020								3,616,414
Beginning Balance at Mar. 31, 2020	14,985							$ 43									63,962									4	(49,024)
Beginning Balance, Shares at Mar. 31, 2020								1,567,637
Stock-based compensation expense	308																308
Costs relating to financing and purchase agreement							$ (1)																		$ (1)
Shares issued on conversion of preferred shares										$ 2									$ (2)
Shares issued on exercise of warrants	589																589
Shares issued on exercise of warrants, Shares								89,281
Shares issued				$ 1,579								$ 6										$ 1,573
Shares issued, Shares												280,782
Adjustment of fractional shares on reverse stock split, Shares								3
Net loss	(2,922)																										(2,922)
Ending Balance at Jun. 30, 2020	14,538							$ 51									66,429									4	(51,946)
Ending Balance, Shares at Jun. 30, 2020								1,937,703
Stock-based compensation expense	281																281
Shares issued on exercise of warrants	$ 2,491							$ 7									2,484
Shares issued on exercise of warrants, Shares								377,845
Shares issued					$ 5,307	$ 6,822							$ 15	$ 1									$ 5,292	$ 6,821
Shares issued, Shares													731,707	569,043
Adjustment of fractional shares on reverse stock split, Shares								(12)
Restricted stock unit settlements, Shares	236							128
Net loss	$ (3,764)																										(3,764)
Ending Balance at Sep. 30, 2020	25,675							$ 74									81,307									4	(55,710)
Ending Balance, Shares at Sep. 30, 2020								3,616,414
Beginning Balance at Dec. 31, 2020	37,286							$ 76									97,640									4	(60,434)
Beginning Balance, Shares at Dec. 31, 2020								6,111,735
Stock-based compensation expense	542																542
Shares issued on exercise of warrants	236																236
Shares issued on exercise of warrants, Shares								35,217
Shares issued	23																23
Shares issued, Shares								2,965
Net loss	(7,999)																										(7,999)
Ending Balance at Mar. 31, 2021	30,088							$ 76									98,441									4	(68,433)
Ending Balance, Shares at Mar. 31, 2021								6,149,917
Beginning Balance at Dec. 31, 2020	$ 37,286							$ 76									97,640									4	(60,434)
Beginning Balance, Shares at Dec. 31, 2020								6,111,735
Restricted stock unit settlements, Shares	231
Net loss	$ (26,001)
Ending Balance at Sep. 30, 2021	34,700							$ 79									121,052									4	(86,435)
Ending Balance, Shares at Sep. 30, 2021								9,453,542
Beginning Balance at Mar. 31, 2021	30,088							$ 76									98,441									4	(68,433)
Beginning Balance, Shares at Mar. 31, 2021								6,149,917
Stock-based compensation expense	621																621
Shares issued on exercise of warrants	95																95
Shares issued on exercise of warrants, Shares								14,443
Shares issued	18		$ 21,343								$ 3						18				$ 21,340
Shares issued, Shares								2,149			3,285,714
Net loss	(11,311)																										(11,311)
Ending Balance at Jun. 30, 2021	40,854							$ 79									120,515									4	(79,744)
Ending Balance, Shares at Jun. 30, 2021								9,452,223
Stock-based compensation expense	530																530
Shares issued on exercise of warrants	8																8
Shares issued on exercise of warrants, Shares								1,174
Restricted stock unit settlements	$ (1)																(1)
Restricted stock unit settlements, Shares	231							145
Net loss	$ (6,691)																										(6,691)
Ending Balance at Sep. 30, 2021	$ 34,700							$ 79									$ 121,052									$ 4	$ (86,435)
Ending Balance, Shares at Sep. 30, 2021								9,453,542