Note 7 - Capital and Other Components of Equity (Details Textual)			1 Months Ended	3 Months Ended		12 Months Ended
	Jun. 29, 2020 USD ($)	Feb. 14, 2019 USD ($) shares	Feb. 28, 2019 USD ($)	Jun. 30, 2021 USD ($) $ / shares shares	Jun. 30, 2020 USD ($) shares	Mar. 31, 2021 USD ($)	Jun. 30, 2021 $ / shares shares	May 09, 2018 $ / shares shares
At-the-market Sales Agreement, Common Stock, Maximum Amount | $	$ 75,000,000	$ 30,000,000
At-the-market Sales Agreement, Term (Year)		3 years
At-the-market Sales Agreement, Underwriter Fees, Percentage of Sales	3.00%
Write Off of Deferred Financing Costs of At-the-Market Program | $			$ 115,000	$ 0	$ 121,000
Proceeds from Issuance of Common Stock, Net | $						$ 59,300,000
Warrants Issued in May 2018 [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares) | shares				1			1	1
Class of Warrant or Right, Exercise Price of Warrants or Rights (in CAD per share) | $ / shares							$ 1.31	$ 1.31
Warrants Issued December 27, 2017 [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares) | shares				1			1
Class of Warrant or Right, Exercise Price of Warrants or Rights (in CAD per share) | $ / shares				$ 1.26
Broker Warrants Issued May 2018 [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares) | shares				1			1
Class of Warrant or Right, Exercise Price of Warrants or Rights (in CAD per share) | $ / shares							$ 1.05
Broker Warrants Issued December 2017 [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares) | shares				1			1
Class of Warrant or Right, Exercise Price of Warrants or Rights (in CAD per share) | $ / shares				$ 1.2625
Warrants Issued in Connection with Public Offering February 2017 [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares) | shares				1			1
Class of Warrant or Right, Exercise Price of Warrants or Rights (in CAD per share) | $ / shares							$ 2.15
At-the-market Offering [Member]
Stock Issued During Period, Shares, New Issues (in shares) | shares		0		0	2,300,000
Proceeds from Issuance of Common Stock, Net | $				$ 1,800,000
Commission Costs Related to Share Sale | $				$ 84,000
Sale of Stock, Average Price Per Share (in dollars per share) | $ / shares				$ 0.81
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs | $				$ 10,000
Minimum [Member]
At-the-market Sales Agreement, Underwriter Fees, Percentage of Sales		3.00%
Maximum [Member]
At-the-market Sales Agreement, Underwriter Fees, Percentage of Sales		4.00%