Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balance at Dec. 31, 2019	$ 68,336	$ 12	$ 326,810	$ 34	$ (258,520)
Balance (in shares) at Dec. 31, 2019		12,040,835
Stock-based compensation expense	3,627		3,627
Stock-based compensation expense		51,056
Issuance of common stock from ESPP purchases and stock option exercises	435		435
Issuance of common stock from ESPP purchases and stock option exercises, shares		82,853
Issuance of common stock for public offering, net of issuance costs	59,941	$ 10	59,931
Issuance of common stock for public offering, net of issuance costs, shares		9,923,076
Unrealized loss on available-for-sale debt securities	(29)			(29)
Net loss	(56,241)				(56,241)
Balance at Dec. 31, 2020	76,069	$ 22	390,803	5	(314,761)
Balance (in shares) at Dec. 31, 2020		22,097,820
Stock-based compensation expense	3,405		3,405
Stock-based compensation expense		56,912
Issuance of common stock from ESPP purchases and stock option exercises	303		303
Issuance of common stock from ESPP purchases and stock option exercises, shares		69,975
Issuance of common stock for public offering, net of issuance costs	49,250	$ 9	49,241
Issuance of common stock for public offering, net of issuance costs, shares		9,185,000
Unrealized loss on available-for-sale debt securities	(5)			$ (5)
Net loss	(87,933)				(87,933)
Balance at Dec. 31, 2021	$ 41,089	$ 31	$ 443,752		$ (402,694)
Balance (in shares) at Dec. 31, 2021		31,409,707