Condensed Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock [Member]	Preferred Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss [Member]
Beginning Balance, Value at Dec. 31, 2020	$ 184,897	$ 10	$ 36,127	$ 1,137,470	$ (988,713)	$ 3
Beginning Balance, Shares at Dec. 31, 2020		101,627,070	337,800
Exercise of stock options and vesting of restricted stock units, Value	199			199
Exercise of stock options and vesting of restricted stock units, Shares		188,000
Stock-based compensation	6,943			6,943
Issuance of shares under employee stock purchase plan, Value	1,191			1,191
Issuance of shares under employee stock purchase plan, Shares		146,049
Issuance of shares of common stock in lieu of board fees	72			72
Issuance of shares of common stock in lieu of board fees, Shares		7,632
Unrealized (loss) gain on available-for-sale securities	3					3
Net loss	(70,274)				(70,274)
Ending Balance, Value at Mar. 31, 2021	123,031	$ 10	$ 36,127	1,145,875	(1,058,987)	6
Ending Balance, Shares at Mar. 31, 2021		101,968,751	337,800
Beginning Balance, Value at Dec. 31, 2020	184,897	$ 10	$ 36,127	1,137,470	(988,713)	3
Beginning Balance, Shares at Dec. 31, 2020		101,627,070	337,800
Unrealized (loss) gain on available-for-sale securities	(5)
Net loss	(134,637)
Ending Balance, Value at Jun. 30, 2021	67,629	$ 10	$ 36,127	1,154,844	(1,123,350)	(2)
Ending Balance, Shares at Jun. 30, 2021		102,249,517	337,800
Beginning Balance, Value at Mar. 31, 2021	123,031	$ 10	$ 36,127	1,145,875	(1,058,987)	6
Beginning Balance, Shares at Mar. 31, 2021		101,968,751	337,800
Issuance of common stock, Value	1,534			1,534
Issuance of common stock, Shares		182,866
Exercise of stock options and vesting of restricted stock units, Value	717			717
Exercise of stock options and vesting of restricted stock units, Shares		93,237
Stock-based compensation	6,679			6,679
Issuance of shares of common stock in lieu of board fees	39			39
Issuance of shares of common stock in lieu of board fees, Shares		4,663
Unrealized (loss) gain on available-for-sale securities	(8)					(8)
Net loss	(64,363)				(64,363)
Ending Balance, Value at Jun. 30, 2021	67,629	$ 10	$ 36,127	1,154,844	(1,123,350)	(2)
Ending Balance, Shares at Jun. 30, 2021		102,249,517	337,800
Beginning Balance, Value at Dec. 31, 2021	(20,688)	$ 11	$ 36,127	1,183,006	(1,239,835)	3
Beginning Balance, Shares at Dec. 31, 2021		106,097,528	337,800
Issuance of common stock, Value	81,828	$ 6		81,822
Issuance of common stock, Shares		58,139,825
Vesting of restricted stock units		276,761
Stock-based compensation	5,238			5,238
Issuance of shares under employee stock purchase plan, Value	391			391
Issuance of shares under employee stock purchase plan, Shares		308,473
Issuance of shares of common stock in lieu of board fees	51			51
Issuance of shares of common stock in lieu of board fees, Shares		45,109
Unrealized (loss) gain on available-for-sale securities	(194)					(194)
Net loss	(55,505)				(55,505)
Ending Balance, Value at Mar. 31, 2022	11,121	$ 17	$ 36,127	1,270,508	(1,295,340)	(191)
Ending Balance, Shares at Mar. 31, 2022		164,867,696	337,800
Beginning Balance, Value at Dec. 31, 2021	(20,688)	$ 11	$ 36,127	1,183,006	(1,239,835)	3
Beginning Balance, Shares at Dec. 31, 2021		106,097,528	337,800
Unrealized (loss) gain on available-for-sale securities	(255)
Net loss	(91,249)
Ending Balance, Value at Jun. 30, 2022	(20,281)	$ 17		1,311,038	(1,331,084)	(252)
Ending Balance, Shares at Jun. 30, 2022		168,364,752
Beginning Balance, Value at Mar. 31, 2022	11,121	$ 17	$ 36,127	1,270,508	(1,295,340)	(191)
Beginning Balance, Shares at Mar. 31, 2022		164,867,696	337,800
Vesting of restricted stock units		83,768
Issuance of Series A Convertible Preferred Stock, net of commissions and beneficial conversion charge, Value			$ (36,127)	36,127
Issuance of Series A Convertible Preferred Stock, net of commissions and beneficial conversion charge, Shares		3,378,000	(337,800)
Stock-based compensation	4,400			4,400
Issuance of shares of common stock in lieu of board fees	51			51
Issuance of shares of common stock in lieu of board fees, Shares		35,288
Offering costs	(48)			(48)
Unrealized (loss) gain on available-for-sale securities	(61)					(61)
Net loss	(35,744)				(35,744)
Ending Balance, Value at Jun. 30, 2022	$ (20,281)	$ 17		$ 1,311,038	$ (1,331,084)	$ (252)
Ending Balance, Shares at Jun. 30, 2022		168,364,752