Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Rights Offering [Member] Common Stock [Member]	Rights Offering [Member] Additional Paid-in Capital [Member]	Rights Offering [Member] AOCI Attributable to Parent [Member]	Rights Offering [Member] Retained Earnings [Member]	Rights Offering [Member]	Private Placement [Member] Common Stock [Member]	Private Placement [Member] Additional Paid-in Capital [Member]	Private Placement [Member] AOCI Attributable to Parent [Member]	Private Placement [Member] Retained Earnings [Member]	Private Placement [Member]	ATM Offering [Member] Common Stock [Member]	ATM Offering [Member] Additional Paid-in Capital [Member]	ATM Offering [Member] AOCI Attributable to Parent [Member]	ATM Offering [Member] Retained Earnings [Member]	ATM Offering [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Total
Balance (in shares) at Dec. 31, 2019																20,825,000
Balance at Dec. 31, 2019																$ 21	$ 153,401	$ 4	$ (122,689)	$ 30,737
Issuance of common stock upon exercise of stock options (in shares)																175,000
Issuance of common stock upon exercise of stock options																$ 0	887	0	0	887
Issuance of shares under employee stock purchase plan (in shares)																83,000
Issuance of shares under employee stock purchase plan																$ 0	490	0	0	490
Issuance of shares upon exercise of warrants (in shares)																187,000
Issuance of shares upon exercise of warrants																$ 0	1,127	0	0	1,127
Issuance of common stock, shares (in shares)	4,280,000
Issuance of common stock	$ 4	$ 29,430	$ 0	$ 0	$ 29,434
Stock-based compensation expense																0	10,075	0	0	10,075
Unrealized gain (loss) on available-for-sale securities																0	0	(5)	0	(5)
Net loss																$ 0	0	0	(49,851)	(49,851)
Balance (in shares) at Dec. 31, 2020																25,550,000
Balance at Dec. 31, 2020																$ 25	195,410	(1)	(172,540)	22,894
Issuance of common stock upon exercise of stock options (in shares)																54,000
Issuance of common stock upon exercise of stock options																$ 0	616	0	0	616
Issuance of shares under employee stock purchase plan (in shares)																91,000
Issuance of shares under employee stock purchase plan																$ 0	810	0	0	810
Issuance of shares upon exercise of warrants (in shares)																585,000
Issuance of shares upon exercise of warrants																$ 1	3,333	0	0	3,334
Issuance of common stock, shares (in shares)											288,000				288,490
Issuance of common stock											$ 0	$ 7,432	$ 0	$ 0	$ 7,432
Stock-based compensation expense																0	14,601	0	0	14,601
Unrealized gain (loss) on available-for-sale securities																0	0	1	0	1
Net loss																$ 0	0	0	(63,660)	(63,660)
Issuance of common stock as part of debt extinguishment and private investment, net of issuance cost of $106 (in shares)						3,049,000
Issuance of common stock as part of debt extinguishment and private investment, net of issuance cost of $106						$ 3	$ 49,891	$ 0	$ 0	$ 49,894
Issuance of common stock upon vesting of restricted stock units, net of shares withheld for employee taxes (in shares)																99,000
Issuance of common stock upon vesting of restricted stock units, net of shares withheld for employee taxes																$ 0	(232)	0	0	(232)
Balance (in shares) at Dec. 31, 2021																29,716,000
Balance at Dec. 31, 2021																$ 29	271,861	0	(236,200)	35,690
Issuance of shares under employee stock purchase plan (in shares)																188,000
Issuance of shares under employee stock purchase plan																$ 1	485	0	0	486
Issuance of shares upon exercise of warrants (in shares)																14,000
Issuance of shares upon exercise of warrants																$ 0	26	0	0	26
Issuance of common stock, shares (in shares)	7,317,000
Issuance of common stock	$ 7	$ 14,857	$ 0	$ 0	$ 14,864
Stock-based compensation expense																0	5,191	0	0	5,191
Unrealized gain (loss) on available-for-sale securities																				0
Net loss																$ 0	0	0	(58,505)	(58,505)
Balance (in shares) at Dec. 31, 2022																37,235,000
Balance at Dec. 31, 2022																$ 37	$ 292,420	$ 0	$ (294,705)	$ (2,248)