Statements of Convertible Preferred Stock and Stockholders' Equity - USD ($) $ in Thousands	Convertible preferred stock series A [Member]	Convertible preferred stock series B [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock, Common [Member]	Retained Earnings [Member]	Total
Balance at Dec. 31, 2021	$ 5,584	$ 6	$ 75	$ 532,641	$ (206)	$ (498,675)	$ 33,841
Balance, shares at Dec. 31, 2021	22,387	5,610,121	74,618,240
Stock issued for the exercise of stock options and stock appreciation rights				102			102
Stock issued for the exercise of stock options and stock appreciation rights, shares			92,377
Stock-based compensation				10,576			10,576
Stock-based compensation, shares			110,726
Components of net loss						(18,292)	(18,292)
Employee stock purchase plan				118			118
Employee stock purchase plan, shares			44,783
Preferred stock conversion	$ (1)			1			1
Preferred stock conversion, shares	(4)		8,333
Balance at Dec. 31, 2022	$ 5,583	$ 6	$ 75	543,438	(206)	(516,967)	26,346
Balance, shares at Dec. 31, 2022	22,383	5,610,121	74,874,459
Stock issued for the exercise of stock options and stock appreciation rights				(15)			(15)
Stock issued for the exercise of stock options and stock appreciation rights, shares			34,125
Stock-based compensation				10,623			10,623
Stock-based compensation, shares			319,019
Components of net loss						(20,713)	(20,713)
Employee stock purchase plan				96			96
Employee stock purchase plan, shares			56,966
Preferred stock conversion	$ (6)	$ (6)	$ 6	6			6
Preferred stock conversion, shares	(25)	(5,610,121)	5,665,128
Balance at Dec. 31, 2023	$ 5,577		$ 81	$ 554,148	$ (206)	$ (537,680)	$ 16,343
Balance, shares at Dec. 31, 2023	22,358		80,949,697