Note 12 - Capital and Other Components of Equity (Details Textual)				12 Months Ended
	Nov. 10, 2021 USD ($)	Jun. 29, 2020 USD ($) shares	Feb. 14, 2019 USD ($)	Mar. 31, 2022 USD ($) shares	Mar. 31, 2022 Vote $ / shares shares	Mar. 31, 2021 USD ($) $ / shares shares	Mar. 31, 2022 Vote $ / shares shares	May 09, 2018 $ / shares shares
At-the-market Sales Agreement, Common Stock, Maximum Amount | $	$ 75,000,000	$ 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 | $				$ 0		$ 264,000
Proceeds from exercise of warrants | $				$ 0		$ 183,000
Warrants Issued in May 2018 [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)					1		1	1
Class of Warrant or Right, Exercise Price of Warrants or Rights (in CAD per share) | $ / shares					$ 10.48			$ 10.48
Warrants Issued December 2017 [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)					1		1
Class of Warrant or Right, Exercise Price of Warrants or Rights (in CAD per share) | $ / shares							$ 10.08
Broker Warrants Issued May 2018 [Member]
Class of Warrant or Right, Exercised During Period (in shares)						222,975
Class of Warrant or Right, Exercised During Period, Exercise Price (in dollars per share) | $ / shares						$ 0.83
Proceeds from exercise of warrants | $						$ 183,000
Broker Warrants Issued December 2017 [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)					1		1
Class of Warrant or Right, Exercise Price of Warrants or Rights (in CAD per share) | $ / shares							$ 10.10
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)					1		1
Class of Warrant or Right, Exercise Price of Warrants or Rights (in CAD per share) | $ / shares					$ 17.20
At-the-market Offering [Member]
Stock Issued During Period, Shares, New Issues (in shares)		0		0		14,700,000
Cost Related to Prospectus Supplement Amount | $	$ 198,000
Proceeds from Issuance of Common Stock, Net | $						$ 59,300,000
Commission Costs Related to Share Sale | $						$ 2,000,000.0
Sale of Stock, Average Price Per Share (in dollars per share) | $ / shares						$ 4.16
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs | $						$ 18,000
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%
Common Class A [Member]
Common Stock, Votes Per Share | Vote					1		1
Common Class B [Member]
Common Stock, Votes Per Share | Vote					10		10
Common Stock, Dividend Rate, Percentage				5.00%
Common Stock, Redemption Price Per Share (in CAD per share) | $ / shares					$ 0.80
Common Stock, Shares, Issued, Total (in shares)					0		0
Common Stock, Shares, Outstanding, Ending Balance (in shares)					0		0
Common Class C [Member]
Common Stock, Dividend Rate, Percentage				5.00%
Common Stock, Redemption Price Per Share (in CAD per share) | $ / shares					$ 0.20
Common Stock, Shares, Issued, Total (in shares)					0		0
Common Stock, Shares, Outstanding, Ending Balance (in shares)					0		0
Common Class D and Common Class E [Member]
Common Stock, Shares, Issued, Total (in shares)					0		0
Common Stock, Shares, Outstanding, Ending Balance (in shares)					0		0
Common Class D and Common Class E [Member] | Minimum [Member]
Common Stock, Dividend Rate, Percentage				0.50%
Common Class D and Common Class E [Member] | Maximum [Member]
Common Stock, Dividend Rate, Percentage				2.00%