LIQUIDITY (Details) - USD ($) $ in Thousands		3 Months Ended	9 Months Ended		12 Months Ended
	Oct. 01, 2021	Sep. 30, 2021	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Cash balances		$ 118,969	$ 118,969	$ 5,480	$ 50,315
Issuance of common stock, net			$ 81,865	$ 13,530
Cantor
Number of common stock issued	637,200
Issuance of common stock, net	$ 2,300
Cantor | Controlled Equity Offering Sales Agreement
Number of common stock issued			9,300,000
Issuance of common stock, net			$ 47,300
Lincoln Park | December 2020 PA
Number of common stock issued		1,100,000	6,100,000
Issuance of common stock, net		$ 4,000	$ 34,600
Amount available for future sales		$ 50,000	$ 50,000
Registered share available for future sales		9,700,252	9,700,252
enCore
Elimination of bonding liability					9,300
Elimination of asset retirement obligations					5,200
Annual expenditures related to reclamation and compliance costs					4,000
Common stock received and royalty interest retained					$ 1,800
Issuance of common stock, net	$ 3,600