CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Gain (Loss)
Balances at Dec. 31, 2020	$ 210,947	$ 310	$ 1,366,188	$ (1,155,629)	$ 78
Balances (in shares) at Dec. 31, 2020		310,566,853
Increase (Decrease) in Stockholders' Equity
Net Income (Loss)	(116,112)			(116,112)
Other comprehensive income (loss)	(251)				(251)
Issuance of common stock in connection with at market offering, net of issuance costs	20,385	$ 11	20,374
Issuance of common stock in connection with at market offering, net of issuance costs (in shares)		10,571,556
Issuance of common stock in connection exercise of warrants	2,479	$ 2	2,477
Issuance of common stock in connection exercise of warrants (in shares)		1,906,341
Stock-based compensation related to issuance of common stock and options in exchange for services	91		91
Stock-based compensation related to issuance of common stock and options in exchange for services (in shares)		20,783
Issuances of common stock under equity plans	797	$ 1	796
Issuances of common stock under equity plans (in shares)		666,058
Stock-based compensation for equity-based awards to employees and directors	8,080		8,080
Balances at Dec. 31, 2021	126,416	$ 324	1,398,006	(1,271,741)	(173)
Balances (in shares) at Dec. 31, 2021		323,731,591
Increase (Decrease) in Stockholders' Equity
Net Income (Loss)	(141,901)			(141,901)
Other comprehensive income (loss)	(68)				(68)
Foreign currency translation adjustment	22				22
Issuance of common stock, pre-funded warrant and warrants to purchase common stock in public offering, net of issuance costs	69,916	$ 53	69,863
Issuance of common stock, pre-funded warrant and warrants to purchase common stock in public offering, net of issuance costs (in shares)		53,333,334
Issuance of common stock in connection exercise of warrants	15,163	$ 12	15,151
Issuance of common stock in connection exercise of warrants (in shares)		11,663,387
Stock-based compensation related to issuance of common stock and options in exchange for services	264		264
Stock-based compensation related to issuance of common stock and options in exchange for services (in shares)		15,962
Issuances of common stock under equity plans	2,185	$ 1	2,184
Issuances of common stock under equity plans (in shares)		1,518,250
Stock-based compensation for equity-based awards to employees and directors	8,001		8,001
Balances at Dec. 31, 2022	$ 79,998	$ 390	1,493,469	(1,413,642)	(219)
Balances (in shares) at Dec. 31, 2022	390,262,524	390,262,524
Increase (Decrease) in Stockholders' Equity
Net Income (Loss)	$ (184,127)			(184,127)
Other comprehensive income (loss)	431				431
Foreign currency translation adjustment	(27)				(27)
Issuance of common stock, pre-funded warrant and warrants to purchase common stock in public offering, net of issuance costs	213,337	$ 68	213,269
Issuance of common stock, pre-funded warrant and warrants to purchase common stock in public offering, net of issuance costs (in shares)		68,007,741
Issuance of common stock in connection exercise of warrants	105,912	$ 78	105,834
Issuance of common stock in connection exercise of warrants (in shares)		77,349,858
Stock-based compensation related to issuance of common stock and options in exchange for services	829	$ 1	828
Stock-based compensation related to issuance of common stock and options in exchange for services (in shares)		36,864
Issuances of common stock under equity plans	13,070	$ 8	13,062
Issuances of common stock under equity plans (in shares)		9,255,228
Stock-based compensation for equity-based awards to employees and directors	18,526		18,526
Balances at Dec. 31, 2023	$ 247,949	$ 545	$ 1,844,988	$ (1,597,769)	$ 185
Balances (in shares) at Dec. 31, 2023	544,912,215	544,912,215