STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid In Capital [Member]	Accumulated Deficit [Member]
Balance at Dec. 31, 2020	$ 123,982	$ 215	$ 887,868	$ (764,101)
Balance (in shares) at Dec. 31, 2020		214,591,906
Stock-based compensation	10,774		10,774
Exercise of employee stock options	$ 1,036		1,036
Exercise of employee stock options (in shares)	363,109	363,109
Common stock issuance		5,991
Restricted stock awards		$ 1	(1)
Restricted stock awards (in shares)		1,601,224
Cancelled restricted common stock (in shares)		(434,787)
Issuance of warrants	$ 1,016		1,016
Net loss	(78,751)			(78,751)
Balance at Dec. 31, 2021	58,057	$ 216	900,693	(842,852)
Balance (in shares) at Dec. 31, 2021		216,127,443
Stock-based compensation	3,528		3,528
Exercise of employee stock options	$ 21		21
Exercise of employee stock options (in shares)	26,250	26,250
Restricted stock awards (in shares)		280,000
Cancelled restricted common stock (in shares)		(232,901)
Repurchase of common stock	$ (45)			(45)
Repurchase of common stock (in shares)		(18,750)
Issuance of common stock, net of expenses	14,724	$ 24	14,700
Issuance of common stock, net of expenses (in shares)		24,228,719
Net loss	(37,730)			(37,730)
Balance at Dec. 31, 2022	$ 38,555	$ 240	$ 918,942	$ (880,627)
Balance (in shares) at Dec. 31, 2022		240,410,761