Condensed Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2022		208,150,021
Beginning balance at Dec. 31, 2022	$ 126,259	$ 0	$ 0	$ 1,998,314	$ (3,488)	$ (1,868,567)
Treasury stock (in shares) beginning balance at Dec. 31, 2022			0
Increase (Decrease) in Stockholders' Equity
Stock-based compensation expense	5,320			5,320
Shares issued upon vesting of restricted stock units and for exercises of stock options and warrants (in shares)		697,815
Shares issued upon vesting of restricted stock units and for exercises of stock options	0
Shares issued for accrued compensation (in shares)		(2,206,469)
Shares issued for accrued compensation	3,361			3,361
Shares issued as payment for services (in shares)		465,808
Shares issued as payment for services	545			545
Shares issued in public offering, net of issuance costs (in shares)		43,962,640
Shares issued in public offerings, net of issuance costs	72,808			72,808
Net loss	(43,053)					(43,053)
Other comprehensive income (loss)	970				970
Ending balance (in shares) at Jun. 30, 2023		255,482,753
Ending balance at Jun. 30, 2023	166,210	$ 0	$ 0	2,080,348	(2,518)	(1,911,620)
Treasury stock (in shares) ending balance at Jun. 30, 2023			0
Beginning balance (in shares) at Mar. 31, 2023		255,482,753
Beginning balance at Mar. 31, 2023	184,133	$ 0	$ 0	2,078,133	(2,699)	(1,891,301)
Treasury stock (in shares) beginning balance at Mar. 31, 2023			0
Increase (Decrease) in Stockholders' Equity
Stock-based compensation expense	2,188			2,188
Shares issued in public offerings, net of issuance costs	27			27
Net loss	(20,319)					(20,319)
Other comprehensive income (loss)	181				181
Ending balance (in shares) at Jun. 30, 2023		255,482,753
Ending balance at Jun. 30, 2023	$ 166,210	$ 0	$ 0	2,080,348	(2,518)	(1,911,620)
Treasury stock (in shares) ending balance at Jun. 30, 2023			0
Beginning balance (in shares) at Dec. 31, 2023	248,919,096	248,919,096
Beginning balance at Dec. 31, 2023	$ 118,498	$ 0	$ 0	2,084,916	(1,947)	(1,964,471)
Treasury stock (in shares) beginning balance at Dec. 31, 2023			7,479,431
Increase (Decrease) in Stockholders' Equity
Stock-based compensation expense	4,545			4,545
Shares issued upon vesting of restricted stock units and for exercises of stock options and warrants (in shares)		1,197,992	1,197,992
Shares issued upon vesting of restricted stock units and for exercises of stock options	52			52
Shares issued for accrued compensation (in shares)		(2,170,885)	(2,170,885)
Shares issued for accrued compensation	3,039			3,039
Shares issued as payment for services (in shares)		368,178	368,178
Shares issued as payment for services	528			528
Net loss	(82,530)					(82,530)
Other comprehensive income (loss)	$ (962)				(962)
Ending balance (in shares) at Jun. 30, 2024	252,656,151	252,656,151
Ending balance at Jun. 30, 2024	$ 43,170	$ 0	$ 0	2,093,080	(2,909)	(2,047,001)
Treasury stock (in shares) ending balance at Jun. 30, 2024			3,742,376
Beginning balance (in shares) at Mar. 31, 2024		250,248,808
Beginning balance at Mar. 31, 2024	97,019	$ 0	$ 0	2,088,025	(2,797)	(1,988,209)
Treasury stock (in shares) beginning balance at Mar. 31, 2024			6,149,719
Increase (Decrease) in Stockholders' Equity
Stock-based compensation expense	1,964			1,964
Shares issued upon vesting of restricted stock units and for exercises of stock options and warrants (in shares)		236,458	236,458
Shares issued upon vesting of restricted stock units and for exercises of stock options	52			52
Shares issued for accrued compensation (in shares)		(2,170,885)	(2,170,885)
Shares issued for accrued compensation	3,039			3,039
Net loss	(58,792)					(58,792)
Other comprehensive income (loss)	$ (112)				(112)
Ending balance (in shares) at Jun. 30, 2024	252,656,151	252,656,151
Ending balance at Jun. 30, 2024	$ 43,170	$ 0	$ 0	$ 2,093,080	$ (2,909)	$ (2,047,001)
Treasury stock (in shares) ending balance at Jun. 30, 2024			3,742,376