Consolidated Statements of Changes in Stockholders' Deficit - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Balance (in shares) at Dec. 31, 2019		33,562,885
Balance at Dec. 31, 2019	$ (6,122)	$ 34	$ 124,318	$ (130,474)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Fair value of warrants issued	735		735
Common Stock issued upon public equity offering (in shares)		930,933
Common Stock issued upon public equity offering	6,528	$ 1	6,527
Costs of public equity offering	(473)		(473)
Shares issued under employee stock purchase plan (in shares)		32,986
Shares issued under employee stock purchase plan	158		158
Exercise of stock options (in shares)		500
Exercise of stock options	2		2
Vested restricted stock units (in shares)		41,950
Vested restricted stock units	(99)		(99)
Share-based compensation expense	6,557		6,557
Net loss	(55,783)			(55,783)
Balance (in shares) at Dec. 31, 2020		34,569,254
Balance at Dec. 31, 2020	(48,497)	$ 35	137,725	(186,257)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock issued upon public equity offering (in shares)		6,550,486
Common Stock issued upon public equity offering	31,069	$ 6	31,063
Costs of public equity offering	(1,291)		(1,291)
Shares issued under employee stock purchase plan (in shares)		40,146
Shares issued under employee stock purchase plan	158		158
Exercise of stock options (in shares)		61,000
Exercise of stock options	185		185
Vested restricted stock units (in shares)		7,850
Vested restricted stock units	(14)		(14)
Share-based compensation expense	6,795		6,795
Net loss	(70,539)			(70,539)
Balance (in shares) at Dec. 31, 2021		41,228,736
Balance at Dec. 31, 2021	$ (82,134)	$ 41	$ 174,621	$ (256,796)