Note 7 - Income and Mining Taxes - Changes in the Valuation Allowance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Balance at beginning of year	$ (77,210)	$ (86,634)	$ (94,981)
Increase Due to Uncertainty of Recovery [Member]
Valuation allowance, deferred tax asset, increase (decrease)	(20,304)	786	686
Decrease Related to Utilization and Expiration [Member]
Valuation allowance, deferred tax asset, increase (decrease)	58,362	8,638	1,756
Decrease Due to Change in Circumstances and Release of Valuation Allowance [Member]
Valuation allowance, deferred tax asset, increase (decrease)	(39,152)	(77,210)	(86,634)
Klondex Mines Ltd [Member] | Business Acquisition [Member]
Valuation allowance, deferred tax asset, increase (decrease)	$ 0	$ 0	$ 5,905