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 [Member]	AOCI Attributable to Parent [Member]	Total
Beginning balance, value at Dec. 31, 2020	$ 5,605	$ 6	$ 74	$ 522,710	$ (206)	$ (487,959)	$ 34,625
Beginning balance, shares at Dec. 31, 2020	22,513	5,610,121	73,694,203
Stock issued for the exercise of stock options and stock appreciation rights			$ 1	429			430
Issuance of common stock, shares			332,232
Stock-based compensation				9,363			9,363
Share-based compensation, shares			325,954
Components of net loss						(10,716)	(10,716)
Employee stock purchase plan				118			118
Employee stock purchase plan, shares			19,699
Preferred stock conversion	$ (21)			21			21
Preferred stock conversion, shares	(126)		246,152
Ending balance, value at Dec. 31, 2021	$ 5,584	$ 6	$ 75	532,641	(206)	(498,675)	33,841
Ending 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
Issuance of common stock, shares			92,377				131,375
Stock-based compensation				10,576			$ 10,576
Share-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
Ending balance, value at Dec. 31, 2022	$ 5,583	$ 6	$ 75	$ 543,438	$ (206)	$ (516,967)	$ 26,346
Ending balance, shares at Dec. 31, 2022	22,383	5,610,121	74,874,459