Statements of Convertible Preferred Stock and Stockholders' Equity (Unaudited) - 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, 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				33			33
Stock issued for the exercise of stock options, shares			29,188
Stock-based compensation				2,655			2,655
Stock-based compensation, shares			144,054
Components of net loss						(5,347)	(5,347)
Employee stock purchase plan				23			23
Employee stock purchase plan, shares			11,798
Balance at Mar. 31, 2023	$ 5,583	$ 6	$ 75	546,149	(206)	(522,314)	23,710
Balance, shares at Mar. 31, 2023	22,383	5,610,121	75,059,499
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
Stock issued for the exercise of stock options				8			8
Stock issued for the exercise of stock options, shares			9,550
Stock-based compensation				2,589			2,589
Stock-based compensation, shares			161,474
Components of net loss						(4,507)	(4,507)
Employee stock purchase plan				22			22
Employee stock purchase plan, shares			13,388
Preferred stock conversion	$ (113)		$ 1	111			112
Preferred stock conversion, shares	(450)		998,668
Balance at Mar. 31, 2024	$ 5,464		$ 82	$ 556,878	$ (206)	$ (542,187)	$ 14,567
Balance, shares at Mar. 31, 2024	21,908		82,132,777