Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]
Beginning balance at Dec. 31, 2021	$ 169,476	$ 4	$ 553,014	$ (383,542)
Beginning balance, shares at Dec. 31, 2021		43,652,000
Stock-based compensation expense	$ 3,378		3,378
Exercise of stock options, shares	0
Proceeds from issuance of ESPP shares	$ 142		142
Issuance of common stock under 2018 employee stock purchase plan, shares		44,000
Net loss	(29,833)			(29,833)
Ending balance at Mar. 31, 2022	143,163	$ 4	556,534	(413,375)
Ending balance, shares at Mar. 31, 2022		43,696,000
Beginning balance at Dec. 31, 2022	75,370	$ 4	564,798	(489,432)
Beginning balance, shares at Dec. 31, 2022		43,916,000
Stock-based compensation expense	2,530		2,530
Exercise of stock options	$ 42		42
Exercise of stock options, shares	45,999	46,000
Vesting of restricted stock awards and units, shares		105,000
Proceeds from issuance of ESPP shares	$ 13		13
Issuance of common stock under 2018 employee stock purchase plan, shares		21,000
Net loss	(24,957)			(24,957)
Ending balance at Mar. 31, 2023	$ 52,998	$ 4	$ 567,383	$ (514,389)
Ending balance, shares at Mar. 31, 2023		44,088,000