Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock At-the-market offering	Common Stock	Additional Paid-In Capital At-the-market offering	Additional Paid-In Capital	Accumulated Other Comprehensive (Loss) Gain	Accumulated Deficit	At-the-market offering	Total
Balance, Beginning at Dec. 31, 2018				$ 253,222	$ (233)	$ (140,474)		$ 112,515
Balance, Beginning (in shares) at Dec. 31, 2018		23,187,219
Increase (Decrease) in Stockholders' Equity
Issuance of common stock, net of issuance costs			$ 34,492				$ 34,492
Issuance of common stock, net of issuance costs (in shares)	2,846,641
Issuance of common stock under equity incentive and employee stock purchase plans				1,779				1,779
Issuance of common stock under equity incentive and employee stock purchase plans (in shares)		583,792
Stock-based compensation expense				8,353				8,353
Other comprehensive (loss) gain					12			12
Net loss						(77,187)		(77,187)
Retirement of common stock in exchange for common stock warrant (in shares)		599,997
Balance, Ending at Dec. 31, 2019				297,846	(221)	(217,661)		79,964
Balance, Ending (in shares) at Dec. 31, 2019		27,217,649
Increase (Decrease) in Stockholders' Equity
Issuance of common stock, net of issuance costs			$ 41,871	212,974			$ 41,871	212,974
Issuance of common stock, net of issuance costs (in shares)	2,483,719	13,526,189
Issuance of common stock under equity incentive and employee stock purchase plans				2,799				2,799
Issuance of common stock under equity incentive and employee stock purchase plans (in shares)		517,908
Stock-based compensation expense				7,899				7,899
Other comprehensive (loss) gain					249			249
Net loss						(66,150)		(66,150)
Balance, Ending at Dec. 31, 2020				563,389	28	(283,811)		$ 279,606
Balance, Ending (in shares) at Dec. 31, 2020		43,745,465						43,745,465
Increase (Decrease) in Stockholders' Equity
Issuance of common stock, net of issuance costs				123,804				$ 123,804
Issuance of common stock, net of issuance costs (in shares)		3,503,311
Issuance of common stock under equity incentive and employee stock purchase plans				6,283				6,283
Issuance of common stock under equity incentive and employee stock purchase plans (in shares)		596,614
Stock-based compensation expense				16,395				16,395
Other comprehensive (loss) gain					(327)			(327)
Shares withheld for net settlement of tax withholding upon vesting of restricted stock units				(189)				(189)
Shares withheld for net settlement of tax withholding upon vesting of restricted stock units (in shares)		(7,060)
Net loss						(125,551)		(125,551)
Balance, Ending at Dec. 31, 2021				$ 709,682	$ (299)	$ (409,362)		$ 300,021
Balance, Ending (in shares) at Dec. 31, 2021		47,838,330						47,838,330