STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive (Loss) Income
Beginning balance (in shares) at Dec. 31, 2020		93,599,975
Beginning balance at Dec. 31, 2020	$ 126,112	$ 9	$ 680,872	$ (554,765)	$ (4)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee stock purchase plan (in shares)		386,664
Issuance of common stock under employee stock purchase plan	819		819
Issuance of common stock for services (in shares)		25,989
Issuance of common stock for services	190		190
Issuance of common stock upon exercise of options (in shares)		331,310
Issuance of common stock upon exercise of options	584		584
Issuance of common stock upon vesting of restricted stock units (in shares)		167,158
Taxes paid for net share settlement of equity awards	(106)		(106)
Issuance of common stock in at the market offering (in shares)		35,671,439
Issuance of common stock in at the market offering	101,146	$ 4	101,142
Stock-based compensation	12,039		12,039
Unrealized gains (losses) on available-for-sale securities	(2)				(2)
Net loss	(158,165)			(158,165)
Ending balance (in shares) at Dec. 31, 2021		130,182,535
Ending balance at Dec. 31, 2021	82,617	$ 13	795,540	(712,930)	(6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee stock purchase plan (in shares)		308,356
Issuance of common stock under employee stock purchase plan	195		195
Issuance of common stock for services (in shares)		711,675
Issuance of common stock for services	390		390
Issuance of common stock upon exercise of options (in shares)		14,080
Issuance of common stock upon exercise of options	7		7
Issuance of common stock upon vesting of restricted stock units (in shares)		3,243,828
Issuance of common stock in at the market offering (in shares)		64,114,542
Issuance of common stock in at the market offering	71,625	$ 7	71,618
Stock-based compensation	10,750		10,750
Unrealized gains (losses) on available-for-sale securities	(48)				(48)
Net loss	(67,207)			(67,207)
Ending balance (in shares) at Dec. 31, 2022		198,575,016
Ending balance at Dec. 31, 2022	98,329	$ 20	878,500	(780,137)	(54)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee stock purchase plan (in shares)		435,708
Issuance of common stock under employee stock purchase plan	808		808
Issuance of common stock for services (in shares)		86,095
Issuance of common stock for services	$ 337		337
Issuance of common stock upon exercise of options (in shares)	226,000	225,988
Issuance of common stock upon exercise of options	$ 365		365
Issuance of common stock upon vesting of restricted stock units (in shares)		855,642
Issuance of common stock in at the market offering (in shares)		32,274,741
Issuance of common stock in at the market offering	119,236	$ 3	119,233
Stock-based compensation	13,530		13,530
Unrealized gains (losses) on available-for-sale securities	278				278
Net loss	(66,067)			(66,067)
Ending balance (in shares) at Dec. 31, 2023		232,453,190
Ending balance at Dec. 31, 2023	$ 166,816	$ 23	$ 1,012,773	$ (846,204)	$ 224