SHAREHOLDERS' EQUITY - Stock option activity (Details) - $ / shares	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Number of Stock Options
Outstanding, beginning of period	4,160,000	2,180,000
Granted	1,020,000	1,830,000
Outstanding, end of period	5,180,000	4,010,000
Exercisable, end of period	3,826,250	1,752,500
Non-vested, end of period	1,353,750	2,257,500
Weighted Average Exercise Price
Outstanding, beginning of period (in dollars per share)	$ 1.26	$ 1.18
Granted (in dollars per share)	0.38	1.40
Outstanding, end of period (in dollars per share)	1.08	1.28
Exercisable, end of period (in dollars per share)	1.31	0.92
Non-vested, end of period (in dollars per share)	$ 0.44	$ 1.56