Note 16 - Acquisitions (Details Textual) $ / shares in Units, $ in Thousands			3 Months Ended		12 Months Ended		58 Months Ended
	Jul. 20, 2018 USD ($) $ / shares shares	Jul. 19, 2018 shares	Dec. 31, 2019 shares	Jun. 30, 2019 USD ($)	Dec. 31, 2019 shares	Dec. 31, 2018 shares	Dec. 31, 2020 shares
Common Stock, Shares, Issued, Total (in shares) | shares							538,487,415
Stock Issued During Period, Shares, New Issues (in shares) | shares			21,410,231		21,410,000	2,565,000	28,583,845
Warrants in Connection with Klondex Mines Acquisition [Member]
Class of Warrant or Right, Issued During Period (in shares) | shares	4,136,000
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares) | shares	1
Warrants in Connection with Klondex Mines Acquisition Expiring April 2032 [Member]
Class of Warrant or Right, Outstanding (in shares) | shares	2,068,000
Warrants in Connection with Klondex Mines Acquisition Expiring February 2029 [Member]
Class of Warrant or Right, Outstanding (in shares) | shares	2,068,000
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares	$ 1.57
Klondex Mines Ltd [Member]
Common Stock, Shares, Issued, Total (in shares) | shares	182,048,945	180,499,319
Stock Issued During Period, Shares, New Issues (in shares) | shares		1,549,626
Klondex Mines Ltd [Member]
Business Acquisition, Share Price (in dollars per share) | $ / shares	$ 2.27
Business Acquisition, Percentage of Voting Interests Acquired	100.00%
Business Combination, Consideration, Cash Alternative, Price Per Share (in dollars per share) | $ / shares	$ 2.47
Business Combination, Consideration, Share Alternative, Share Exchange Rate	0.6272
Business Combination Consideration, Combined Alternative, Price Per Share (in dollars per share) | $ / shares	$ 0.8411
Business Combination Consideration, Combined Alternative, Share Exchange Rate	0.4136
Payments to Acquire Businesses, Gross	$ 161,704
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares (in shares) | shares	75,276,176
Stock Issued During Period, Shares, New Issues (in shares) | shares	75,276,176
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares	$ 8.02
Share-based Payment Arrangement, Cash Used to Settle Award	$ 2,000
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable	242,389
Class of Warrant or Right, Issued During Period, Value	9,800
Business Combination, Consideration Transferred, Total	413,923
Business Combination, Subscrition of New Formed Company, Value	7,000
Business Combination, Settlement of Certain Equity Compensation Value	1,500
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Consideration Transferred				$ (300)
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Inventory				(200)
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment				(11,500)
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Accrued Payroll and Related Benefits				(2,100)
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Noncurrent Deferred Tax Liability				(9,800)
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Accounts Payable and Accrued Liabilities				$ 500
Klondex Mines Ltd [Member] | Maximum [Member]
Payments to Acquire Businesses, Gross	$ 153,200
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares (in shares) | shares	75,276,176