Statements of Changes in Stockholders' Deficit - USD ($)	Preferred Stock	Common stock At-the-market sales	Common stock	Additional Paid-in Capital. At-the-market sales	Additional Paid-in Capital.	Accumulated Deficit	At-the-market sales	Total
Balance at Dec. 31, 2021					$ 387,205,000	$ (383,290,000)		$ 3,915,000
Balance (in shares) at Dec. 31, 2021			60,698,000
Increase (decrease) in stockholders' equity
Share-based compensation - stock options and RSUs					764,000			764,000
Issuance of common stock				$ 348,000			$ 348,000
Issuance of common stock (in shares)		512,000
Issuance of common stock upon exercise of options (in shares)	4,850
Conversion of convertible preferred stock (in shares)			6,063,000
Vesting of RSUs	$ (2,425)
Vesting of RSUs (in shares)			35,000
Net loss						(10,385,000)		(10,385,000)
Balance at Mar. 31, 2022					388,317,000	(393,675,000)		(5,358,000)
Balance (in shares) at Mar. 31, 2022	2,425		67,308,000
Balance at Dec. 31, 2021					387,205,000	(383,290,000)		3,915,000
Balance (in shares) at Dec. 31, 2021			60,698,000
Balance at Dec. 31, 2022					403,157,000	(408,702,000)		(5,545,000)
Balance (in shares) at Dec. 31, 2022			859,402
Increase (decrease) in stockholders' equity
Share-based compensation - stock options and RSUs					498,000			498,000
Issuance of common stock				$ 1,003,000			$ 1,003,000
Issuance of common stock (in shares)		72,699
Net loss						(5,390,000)		(5,390,000)
Balance at Mar. 31, 2023					$ 404,658,000	$ (414,092,000)		$ (9,434,000)
Balance (in shares) at Mar. 31, 2023			932,101