NATURE OF OPERATIONS (Details)				3 Months Ended
	Feb. 10, 2023	Mar. 31, 2022 USD ($)	Mar. 15, 2022 USD ($)	Mar. 31, 2023 USD ($) segment	Mar. 31, 2022 USD ($)	Jan. 12, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Number of reportable segments | segment				1
Reverse stock split ratio	0.0556
Net (loss) income				$ (5,622,000)	$ 4,670,000
Cash used in operations				(5,478,000)	(9,039,000)
Cash and investments		$ 51,100,000		30,280,000	51,100,000		$ 30,975,000	$ 42,855,000
Accumulated deficit				(668,506,000)			(662,735,000)
Additional paid-in capital				694,937,000			$ 693,937,000
Debt outstanding				0
Sale of stock, public float threshold				$ 75,000,000
Lincoln Park Equity Purchase Agreement
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Consideration receivable on transaction		$ 30,000,000	$ 30,000,000		$ 30,000,000
Term of equity purchase agreement		36 months	36 months
MST Franchise | Discontinued Operations, Disposed of by Sale
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Additional paid-in capital						$ 5,000,000