CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' DEFICIT - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive income (loss)	Accumulated Deficit
Balance at Dec. 31, 2020	$ 6,118	$ 25	$ 241,649	$ 12	$ (235,568)
Balance (in shares) at Dec. 31, 2020		24,976,142
Share-based compensation expense	1,791		1,791
Exercise of stock options	235		235
Exercise of stock options, shares		217,015
Unrealized loss on short-term investments	(2)			(2)
Net loss	(18,715)				(18,715)
Balance at Mar. 31, 2021	(10,573)	$ 25	243,675	10	(254,283)
Balance (in shares) at Mar. 31, 2021		25,193,157
Balance at Dec. 31, 2020	6,118	$ 25	241,649	12	(235,568)
Balance (in shares) at Dec. 31, 2020		24,976,142
Unrealized loss on short-term investments	(9)
Net loss	(41,101)
Balance at Jun. 30, 2021	(25,517)	$ 26	251,123	3	(276,669)
Balance (in shares) at Jun. 30, 2021		25,919,411
Balance at Mar. 31, 2021	(10,573)	$ 25	243,675	10	(254,283)
Balance (in shares) at Mar. 31, 2021		25,193,157
Share-based compensation expense	1,611		1,611
Exercise of stock options	120		120
Exercise of stock options, shares		60,975
Sale of shares under Open Market Sale Agreement, net	5,718	$ 1	5,717
Sale of shares under open market sale agreement, shares		665,279
Unrealized loss on short-term investments	(7)			(7)
Net loss	(22,386)				(22,386)
Balance at Jun. 30, 2021	(25,517)	$ 26	251,123	3	(276,669)
Balance (in shares) at Jun. 30, 2021		25,919,411
Balance at Dec. 31, 2021	$ (58,004)	$ 26	258,086	(14)	(316,102)
Balance (in shares) at Dec. 31, 2021	26,458,767	26,458,767
Share-based compensation expense	$ 1,848		1,848
Exercise of stock options	58		58
Exercise of stock options, shares		46,358
Sale of shares under Open Market Sale Agreement, net	1,117	$ 1	1,116
Sale of shares under open market sale agreement, shares		314,296
Unrealized loss on short-term investments	(47)			(47)
Net loss	(15,443)				(15,443)
Balance at Mar. 31, 2022	(70,471)	$ 27	261,108	(61)	(331,545)
Balance (in shares) at Mar. 31, 2022		26,819,421
Balance at Dec. 31, 2021	$ (58,004)	$ 26	258,086	(14)	(316,102)
Balance (in shares) at Dec. 31, 2021	26,458,767	26,458,767
Exercise of stock options, shares	48,526
Unrealized loss on short-term investments	$ (96)
Net loss	(30,001)
Balance at Jun. 30, 2022	$ (83,246)	$ 27	262,940	(110)	(346,103)
Balance (in shares) at Jun. 30, 2022	26,821,589	26,821,589
Balance at Mar. 31, 2022	$ (70,471)	$ 27	261,108	(61)	(331,545)
Balance (in shares) at Mar. 31, 2022		26,819,421
Share-based compensation expense	1,830		1,830
Exercise of stock options	2		2
Exercise of stock options, shares		2,168
Unrealized loss on short-term investments	(49)			(49)
Net loss	(14,558)				(14,558)
Balance at Jun. 30, 2022	$ (83,246)	$ 27	$ 262,940	$ (110)	$ (346,103)
Balance (in shares) at Jun. 30, 2022	26,821,589	26,821,589