Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive (Loss) Income	Accumulated Deficit
Balances at Dec. 31, 2019	$ 60,081	$ 3	$ 255,142	$ 51	$ (195,115)
Balances (in shares) at Dec. 31, 2019		29,084,000
Issuance of common stock and pre-funded warrants in connection with public and at-the-market offerings, net of offering costs	153,572	$ 2	153,570
Issuance of common stock and pre-funded warrants in connection with public and at-the-market offerings, net of offering costs (in shares)		18,688,000
Issuance of common stock in connection with exercise of stock options	490		490
Issuance of common stock in connection with exercise of stock options (in shares)		127,000
Issuance of common stock in connection with employee stock purchase plan	366		366
Issuance of common stock in connection with employee stock purchase plan (in shares)		60,000
Stock-based compensation expense	6,256		6,256
Foreign currency translation adjustment	19			19
Unrealized gain (loss) on marketable securities	(59)			(59)
Net loss	(80,893)				(80,893)
Balances at Dec. 31, 2020	139,832	$ 5	415,824	11	(276,008)
Balances (in shares) at Dec. 31, 2020		47,959,000
Issuance of common stock and pre-funded warrants in connection with public and at-the-market offerings, net of offering costs (in shares)		1,000,000
Issuance of common stock in connection with exercise of stock options	1,449		1,449
Issuance of common stock in connection with exercise of stock options (in shares)		313,000
Issuance of common stock in connection with employee stock purchase plan	454		454
Issuance of common stock in connection with employee stock purchase plan (in shares)		83,000
Stock-based compensation expense	8,038		8,038
Foreign currency translation adjustment	(1)			(1)
Unrealized gain (loss) on marketable securities	(30)			(30)
Net loss	(65,801)				(65,801)
Balances at Dec. 31, 2021	$ 83,941	$ 5	425,765	(20)	(341,809)
Balances (in shares) at Dec. 31, 2021		49,355,000
Issuance of common stock in connection with exercise of stock options (in shares)	0
Issuance of common stock and pre-funded warrants in connection with registered direct offering, net of offering costs	$ 42,874	$ 1	42,873
Issuance of common stock and pre-funded warrants in connection with registered direct offering, net of offering costs (in shares)		10,753,000
Issuance of common stock in connection with exercise of pre-funded warrants (in shares)		5,090,000
Issuance of common stock in connection with employee stock purchase plan	222		222
Issuance of common stock in connection with employee stock purchase plan (in shares)		152,000
Stock-based compensation expense	7,111		7,111
Foreign currency translation adjustment	(35)			(35)
Unrealized gain (loss) on marketable securities	7			7
Net loss	(83,815)				(83,815)
Balances at Dec. 31, 2022	$ 50,305	$ 6	$ 475,971	$ (48)	$ (425,624)
Balances (in shares) at Dec. 31, 2022		65,350,000