Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	ATM Agreement	Common Stock	Common Stock ATM Agreement	Additional Paid-in Capital	Additional Paid-in Capital ATM Agreement	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balance at Dec. 31, 2018	$ 108,797		$ 19		$ 158,176		$ (203)	$ (49,195)
Balance, shares at Dec. 31, 2018			19,114,421
Issuance of common stock under employee stock incentive plans	272				272
Issuance of common stock under employee stock incentive plans, shares			93,656
Vesting related to shares of common stock issued pursuant to early exercises	50				50
Stock-based compensation expense	4,007				4,007
Other comprehensive income	7						7
Net loss	(35,087)							(35,087)
Balance at Dec. 31, 2019	78,046		$ 19		162,505		(196)	(84,282)
Balance, shares at Dec. 31, 2019			19,208,077
Issuance of common stock and pre-funded warrants through underwritten offerings	99,161		$ 27		99,134
Issuance of common stock and pre-funded warrants through underwritten offerings, shares			26,984,001
Issuance of common stock under employee stock incentive plans	470				470
Issuance of common stock under employee stock incentive plans, shares			167,665
Vesting related to shares of common stock issued pursuant to early exercises	41				41
Stock-based compensation expense	4,943				4,943
Other comprehensive income	59						59
Net loss	(41,742)							(41,742)
Balance at Dec. 31, 2020	$ 140,978		$ 46		267,093		(137)	(126,024)
Balance, shares at Dec. 31, 2020			46,359,743
Issuance of common stock net of offering costs		$ 100,995		$ 9		$ 100,986
Issuance of common stock net of offering costs, shares	9,352,359			9,352,359
Issuance of common stock under employee stock incentive plans	$ 2,070		$ 1		2,069
Issuance of common stock under employee stock incentive plans, shares			547,645
Vesting related to shares of common stock issued pursuant to early exercises	21				21
Stock-based compensation expense	7,596				7,596
Other comprehensive income	(154)						(154)
Net loss	(54,630)							(54,630)
Balance at Dec. 31, 2021	$ 196,876		$ 56		$ 377,765		$ (291)	$ (180,654)
Balance, shares at Dec. 31, 2021			56,259,747