Condensed Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Total revenues	$ 1,927,000	$ 1,744,000	$ 5,925,000	$ 5,879,000
Operating expenses:
Cost of product revenues	$ 513,000	$ 312,000	$ 1,158,000	$ 1,059,000
Type of cost, good or service [extensible list]	Product Revenue, Net [Member]	Product Revenue, Net [Member]	Product Revenue, Net [Member]	Product Revenue, Net [Member]
Research and development	$ 2,164,000	$ 7,199,000	$ 8,530,000	$ 23,738,000
Selling, general and administrative	3,217,000	3,790,000	9,325,000	11,712,000
Total operating expenses	5,894,000	11,301,000	19,013,000	36,509,000
Loss from operations	(3,967,000)	(9,557,000)	(13,088,000)	(30,630,000)
Other income (expense):
Interest and other income	163,000	653,000	711,000	1,681,000
Interest and other expenses	(364,000)	(700,000)	(1,338,000)	(2,175,000)
Change in fair value of warrant liabilities	(117,000)	7,016,000	(1,913,000)	8,601,000
Issuance cost for warrants		(427,000)		(1,627,000)
Loss on issuance of warrants				(2,033,000)
Other income (expense), net	(318,000)	6,542,000	(2,540,000)	4,447,000
Net loss	(4,285,000)	(3,015,000)	(15,628,000)	(26,183,000)
Net change in unrealized gain (loss) on available-for-sale securities, net of reclassification adjustments and taxes	7,000	(6,000)	14,000	1,000
Total comprehensive loss	$ (4,278,000)	$ (3,021,000)	$ (15,614,000)	$ (26,182,000)
Net loss per share
Net income per share, basic	$ (0.14)	$ (0.11)	$ (0.51)	$ (1.04)
Net income per share, diluted	$ (0.14)	$ (0.14)	$ (0.51)	$ (1.07)
Weighted-average shares used in computing net loss per share
Weighted-average shares used in computing net loss per share, basic	31,039	27,211	30,906	25,175
Weighted-average shares used in computing net loss per share, diluted	31,039	27,511	30,906	25,433
Collaborative Research and Development and Other Revenue [Member]
Total revenues	$ 369,000	$ 506,000	$ 1,471,000	$ 1,657,000
Product Revenue, Net [Member]
Total revenues	$ 1,558,000	$ 1,238,000	$ 4,454,000	$ 4,222,000