Condensed Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	2021 Sales Agreement [Member]	July 2023 Registered Direct Offering [Member]	Common Stock [Member]	Common Stock [Member] 2021 Sales Agreement [Member]	Common Stock [Member] July 2023 Registered Direct Offering [Member]	Common Stock [Member] February 2023 Registered Direct Offering [Member]	Additional paid-in capital [Member]	Additional paid-in capital [Member] 2021 Sales Agreement [Member]	Additional paid-in capital [Member] July 2023 Registered Direct Offering [Member]	Accumulated other comprehensive loss [Member]	Accumulated deficit [Member]
Beginning balance at Dec. 31, 2022	$ 24,985			$ 23				$ 586,357			$ (13)	$ (561,382)
Beginning balance, shares at Dec. 31, 2022				22,785,000
Issuance of common stock in the February 2023 registered direct offering/pursuant to the 2021 Sales Agreement/July 2023 registered direct offering, shares							1,700,000
Stock-based compensation expense from stock options and ESPP shares	2,338							2,338
Net loss	(11,987)											(11,987)
Net change in unrealized loss on available-for-sale securities, net of reclassification adjustments and taxes	6										6
Ending balance at Mar. 31, 2023	15,342			$ 23				588,695			(7)	(573,369)
Ending balance, shares at Mar. 31, 2023				24,485,000
Beginning balance at Dec. 31, 2022	24,985			$ 23				586,357			(13)	(561,382)
Beginning balance, shares at Dec. 31, 2022				22,785,000
Net loss	(26,183)
Ending balance at Sep. 30, 2023	14,406			$ 23				601,960			(12)	(587,565)
Ending balance, shares at Sep. 30, 2023				28,524,000
Beginning balance at Mar. 31, 2023	15,342			$ 23				588,695			(7)	(573,369)
Beginning balance, shares at Mar. 31, 2023				24,485,000
Issuance of common stock in the February 2023 registered direct offering/pursuant to the 2021 Sales Agreement/July 2023 registered direct offering		$ 658							$ 658
Issuance of common stock in the February 2023 registered direct offering/pursuant to the 2021 Sales Agreement/July 2023 registered direct offering, shares					118,000
Issuance of common stock upon exercise of stock options and from the ESPP	23							23
Issuance of common stock upon exercise of stock options and from the ESPP, shares				6,000
Stock-based compensation expense from stock options and ESPP shares	657							657
Net loss	(11,181)											(11,181)
Net change in unrealized loss on available-for-sale securities, net of reclassification adjustments and taxes	1										1
Ending balance at Jun. 30, 2023	5,500			$ 23				590,033			(6)	(584,550)
Ending balance, shares at Jun. 30, 2023				24,609,000
Issuance of common stock in the February 2023 registered direct offering/pursuant to the 2021 Sales Agreement/July 2023 registered direct offering			$ 8,540							$ 8,540
Issuance of common stock in the February 2023 registered direct offering/pursuant to the 2021 Sales Agreement/July 2023 registered direct offering, shares						2,991,000
Issuance of common stock upon warrant exercises	2,726							2,726
Issuance of common stock upon warrant exercises, shares				924,000
Stock-based compensation expense from stock options and ESPP shares	661							661
Net loss	(3,015)											(3,015)
Net change in unrealized loss on available-for-sale securities, net of reclassification adjustments and taxes	(6)										(6)
Ending balance at Sep. 30, 2023	14,406			$ 23				601,960			(12)	(587,565)
Ending balance, shares at Sep. 30, 2023				28,524,000
Beginning balance at Dec. 31, 2023	14,783			$ 23				603,780			(14)	(589,006)
Beginning balance, shares at Dec. 31, 2023				30,334,000
Issuance of common stock in the February 2023 registered direct offering/pursuant to the 2021 Sales Agreement/July 2023 registered direct offering		$ 648							$ 648
Issuance of common stock in the February 2023 registered direct offering/pursuant to the 2021 Sales Agreement/July 2023 registered direct offering, shares					702,000
Stock-based compensation expense from stock options and ESPP shares	508							508
Net loss	(7,643)											(7,643)
Net change in unrealized loss on available-for-sale securities, net of reclassification adjustments and taxes	4										4
Ending balance at Mar. 31, 2024	8,300			$ 23				604,936			(10)	(596,649)
Ending balance, shares at Mar. 31, 2024				31,036,000
Beginning balance at Dec. 31, 2023	14,783			$ 23				603,780			(14)	(589,006)
Beginning balance, shares at Dec. 31, 2023				30,334,000
Net loss	(15,628)
Ending balance at Sep. 30, 2024	1,217			$ 23				605,828				(604,634)
Ending balance, shares at Sep. 30, 2024				31,039,000
Beginning balance at Mar. 31, 2024	8,300			$ 23				604,936			(10)	(596,649)
Beginning balance, shares at Mar. 31, 2024				31,036,000
Issuance of common stock upon exercise of stock options and from the ESPP	3							3
Issuance of common stock upon exercise of stock options and from the ESPP, shares				3,000
Stock-based compensation expense from stock options and ESPP shares	431							431
Net loss	(3,700)											(3,700)
Net change in unrealized loss on available-for-sale securities, net of reclassification adjustments and taxes	3										3
Ending balance at Jun. 30, 2024	5,037			$ 23				605,370			(7)	(600,349)
Ending balance, shares at Jun. 30, 2024				31,039,000
Stock-based compensation expense from stock options and ESPP shares	458							458
Net loss	(4,285)											(4,285)
Net change in unrealized loss on available-for-sale securities, net of reclassification adjustments and taxes	7										$ 7
Ending balance at Sep. 30, 2024	$ 1,217			$ 23				$ 605,828				$ (604,634)
Ending balance, shares at Sep. 30, 2024				31,039,000