Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2022		211,091,425
Beginning balance at Dec. 31, 2022	$ 126,654	$ 2,110	$ 504,767	$ (1,893)	$ (378,330)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Private placement of common stock/ Rights offering of common stock, net of offering costs (in shares)		476,190,471
Private placement of common stock/ Rights offering of common stock, net of offering costs	499,381	$ 4,762	494,619
Issuance of common stock under stock purchase plans and exercise of stock options and warrants (in shares)		403,469
Issuance of common stock under stock purchase plans and exercise of stock options and warrants	651	$ 4	647
Issuance of common stock in lieu of cash for Akeso upfront payment (in shares)		10,000,000
Issuance of common stock in lieu of cash for Akeso upfront payment	45,900	$ 100	45,800
Stock-based compensation	4,650		4,650
Net changes related to short-term investments	3			3
Reclassification of cumulative translation gain (Note 8)	(419)			(419)
Foreign currency translation adjustment	(128)			(128)
Net loss	(557,093)				(557,093)
Ending balance (in shares) at Jun. 30, 2023		697,685,365
Ending balance at Jun. 30, 2023	119,599	$ 6,976	1,050,483	(2,437)	(935,423)
Beginning balance (in shares) at Mar. 31, 2023		697,685,365
Beginning balance at Mar. 31, 2023	133,482	$ 6,976	1,048,608	(1,396)	(920,706)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	1,875		1,875
Net changes related to short-term investments	(965)			(965)
Reclassification of cumulative translation gain (Note 8)	0
Foreign currency translation adjustment	(76)			(76)
Net loss	(14,717)				(14,717)
Ending balance (in shares) at Jun. 30, 2023		697,685,365
Ending balance at Jun. 30, 2023	$ 119,599	$ 6,976	1,050,483	(2,437)	(935,423)
Beginning balance (in shares) at Dec. 31, 2023	701,660,053	701,660,053
Beginning balance at Dec. 31, 2023	$ 77,692	$ 7,017	1,066,381	(2,448)	(993,258)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Private placement of common stock/ Rights offering of common stock, net of offering costs (in shares)		22,222,222
Private placement of common stock/ Rights offering of common stock, net of offering costs	200,000	$ 222	199,778
Issuance of common stock under stock purchase plans and exercise of stock options and warrants (in shares)		437,926
Issuance of common stock under stock purchase plans and exercise of stock options and warrants	697	$ 4	693
Stock-based compensation	20,595		20,595
Net changes related to short-term investments	(34)
Reclassification of cumulative translation gain (Note 8)	0
Foreign currency translation adjustment	82
Net other comprehensive loss	(51)			(51)
Net loss	$ (103,858)				(103,858)
Ending balance (in shares) at Jun. 30, 2024	724,320,201	724,320,201
Ending balance at Jun. 30, 2024	$ 195,075	$ 7,243	1,287,447	(2,499)	(1,097,116)
Beginning balance (in shares) at Mar. 31, 2024		701,974,596
Beginning balance at Mar. 31, 2024	44,210	$ 7,020	1,076,370	(2,449)	(1,036,731)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Private placement of common stock/ Rights offering of common stock, net of offering costs (in shares)		22,222,222
Private placement of common stock/ Rights offering of common stock, net of offering costs	200,000	$ 222	199,778
Issuance of common stock under stock purchase plans and exercise of stock options and warrants (in shares)		123,383
Issuance of common stock under stock purchase plans and exercise of stock options and warrants	212	$ 1	211
Stock-based compensation	11,088		11,088
Net changes related to short-term investments	(45)
Reclassification of cumulative translation gain (Note 8)	0
Foreign currency translation adjustment	92
Net other comprehensive loss	(50)			(50)
Net loss	$ (60,385)				(60,385)
Ending balance (in shares) at Jun. 30, 2024	724,320,201	724,320,201
Ending balance at Jun. 30, 2024	$ 195,075	$ 7,243	$ 1,287,447	$ (2,499)	$ (1,097,116)