Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]
Stockholders Equity, Beginning Balance at Dec. 31, 2020	$ 97,959	$ 11	$ 944,537	$ (846,589)
Stockholders Equity, Beginning Balance, Shares at Dec. 31, 2020		11,128,484
Issuance of common stock	19,632	$ 1	19,631
Issuance of common stock, Shares		1,149,820
Issuance of common stock for exercise of common stock warrants	660		660
Issuance of common stock for exercise of common stock warrant, Shares		49,995
Issuance of common stock for exercise of common stock options	288		288
Issuance of common stock for exercise of common stock options, Shares		21,662
Stock-based compensation	2,931		2,931
Net loss	(19,915)			(19,915)
Stockholders Equity, Ending Balance at Mar. 31, 2021	101,555	$ 12	968,047	(866,504)
Stockholders Equity, Ending Balance, Shares at Mar. 31, 2021		12,349,961
Stockholders Equity, Beginning Balance at Dec. 31, 2021	95,998	$ 16	1,037,230	(941,248)
Stockholders Equity, Beginning Balance, Shares at Dec. 31, 2021		15,571,656
Issuance of common stock	121,905	$ 5	121,900
Issuance of common stock, Shares		4,824,075
Issuance of pre-funded stock warrants	23,397		23,397
Issuance of common stock for exercise of common stock warrants	40,346	$ 3	40,343
Issuance of common stock for exercise of common stock warrant, Shares		3,056,477
Issuance of common stock for exercise of common stock options	4,572		4,572
Issuance of common stock for exercise of common stock options, Shares		348,201
Stock-based compensation	3,332		3,332
Net loss	(27,928)			(27,928)
Stockholders Equity, Ending Balance at Mar. 31, 2022	$ 261,622	$ 24	$ 1,230,774	$ (969,176)
Stockholders Equity, Ending Balance, Shares at Mar. 31, 2022		23,800,409