Condensed Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]	Total
Balance at Dec. 31, 2020	$ 25	$ 195,410	$ (1)	$ (172,540)	$ 22,894
Balance, shares at Dec. 31, 2020	25,550
Balance at Jun. 30, 2021	$ 29	266,223		(206,502)	59,750
Balance, shares at Jun. 30, 2021	29,606
Balance at Dec. 31, 2020	$ 25	195,410	(1)	(172,540)	22,894
Balance, shares at Dec. 31, 2020	25,550
Issuance of common stock as part of debt extinguishment and private investment, net of issuance costs of $100	$ 3	49,891			49,894
Issuance of common stock as part of debt extinguishment and private investment, net of issuance cost of $100, shares	3,049
Issuance of common stock, net of issuance costs		7,432			7,432
Issuance of common stock, net of issuance costs, shares	289
Issuance of common stock upon exercise of stock options		508			508
Issuance of common stock upon exercise of stock options, shares	45
Issuance of common stock under employee stock purchase plan		810			810
Issuance of common stock under employee stock purchase plan, shares	91
Issuance of common stock pursuant to warrant exercise	$ 1	3,333			3,334
Issuance of common stock pursuant to warrant exercise, shares	585
Issuance of common stock upon vesting of restricted stock units, net of shares withheld for employee taxes		(232)			(232)
Issuance of common stock upon vesting of restricted stock units, net of shares withheld for employee taxes, shares	22
Stock-based compensation expense		10,990			10,990
Unrealized gain on available-for-sale securities			$ 1		1
Net loss				(48,244)	(48,244)
Balance at Sep. 30, 2021	$ 29	268,142		(220,784)	47,387
Balance, shares at Sep. 30, 2021	29,631
Balance at Jun. 30, 2021	$ 29	266,223		(206,502)	59,750
Balance, shares at Jun. 30, 2021	29,606
Issuance of common stock under employee stock purchase plan		389			389
Issuance of common stock under employee stock purchase plan, shares	25
Stock-based compensation expense		1,577			1,577
Debt extinguishment and private investment, additional issuance costs		(47)			(47)
Net loss				(14,282)	(14,282)
Balance at Sep. 30, 2021	$ 29	268,142		(220,784)	47,387
Balance, shares at Sep. 30, 2021	29,631
Balance at Dec. 31, 2021	$ 29	271,861		(236,200)	$ 35,690
Balance, shares at Dec. 31, 2021	29,716				29,716
Issuance of common stock, net of issuance costs	$ 7	14,857			$ 14,864
Issuance of common stock, net of issuance costs, shares	7,317
Issuance of common stock under employee stock purchase plan	$ 1	485			486
Issuance of common stock under employee stock purchase plan, shares	188
Issuance of common stock pursuant to warrant exercise		14			14
Issuance of common stock pursuant to warrant exercise, shares	7
Stock-based compensation expense		4,443			4,443
Net loss				(49,308)	(49,308)
Balance at Sep. 30, 2022	$ 37	291,660		(285,508)	$ 6,189
Balance, shares at Sep. 30, 2022	37,228				37,228
Balance at Jun. 30, 2022	$ 37	290,847		(267,469)	$ 23,415
Balance, shares at Jun. 30, 2022	37,126
Issuance of common stock under employee stock purchase plan		113			113
Issuance of common stock under employee stock purchase plan, shares	102
Rights offering, additional issuance costs		(25)			(25)
Issuance of common stock pursuant to warrant exercise		2			2
Stock-based compensation expense		723			723
Net loss				(18,039)	(18,039)
Balance at Sep. 30, 2022	$ 37	$ 291,660		$ (285,508)	$ 6,189
Balance, shares at Sep. 30, 2022	37,228				37,228