Note 18 - Income Taxes - Tax Attributes and Temporary Differences Available to Reduce Future Years' Taxable Income (Details) $ in Thousands	Mar. 31, 2022 USD ($)
Domestic Tax Authority [Member]
Tax losses carried forward	$ 119,352
Domestic Tax Authority [Member] | Research Tax Credit Carryforward [Member]
Carryforwards, without time limitation	21,127
Domestic Tax Authority [Member] | Tax Year 2028 [Member]
Tax losses carried forward	571
Domestic Tax Authority [Member] | Tax Year 2029 [Member]
Tax losses carried forward	1,301
Domestic Tax Authority [Member] | Tax Year 2030 [Member]
Tax losses carried forward	1,656
Domestic Tax Authority [Member] | Tax Year 2031 [Member]
Tax losses carried forward	1,809
Domestic Tax Authority [Member] | Tax Year 2032 [Member]
Tax losses carried forward	1,483
Domestic Tax Authority [Member] | Tax Year 2033 [Member]
Tax losses carried forward	2,877
Domestic Tax Authority [Member] | Tax Year 2035 [Member]
Tax losses carried forward	4,394
Domestic Tax Authority [Member] | Tax Year 2034 [Member]
Tax losses carried forward	3,675
Domestic Tax Authority [Member] | Tax Year 2036 [Member]
Tax losses carried forward	6,465
Domestic Tax Authority [Member] | Tax Year 2037 [Member]
Tax losses carried forward	400
Domestic Tax Authority [Member] | Tax Year 2038 [Member]
Tax losses carried forward	13,866
Domestic Tax Authority [Member] | Tax Year 2039 [Member]
Tax losses carried forward	32,399
Domestic Tax Authority [Member] | Tax Year 2040 [Member]
Tax losses carried forward	23,558
Domestic Tax Authority [Member] | Tax Year 2041 [Member]
Tax losses carried forward	13,988
Domestic Tax Authority [Member] | Tax Year 2042 [Member]
Tax losses carried forward	10,910
State and Local Jurisdiction [Member]
Tax losses carried forward	118,854
State and Local Jurisdiction [Member] | Research Tax Credit Carryforward [Member]
Carryforwards, without time limitation	23,125
State and Local Jurisdiction [Member] | Tax Year 2028 [Member]
Tax losses carried forward	571
State and Local Jurisdiction [Member] | Tax Year 2029 [Member]
Tax losses carried forward	1,296
State and Local Jurisdiction [Member] | Tax Year 2030 [Member]
Tax losses carried forward	1,650
State and Local Jurisdiction [Member] | Tax Year 2031 [Member]
Tax losses carried forward	1,792
State and Local Jurisdiction [Member] | Tax Year 2032 [Member]
Tax losses carried forward	1,460
State and Local Jurisdiction [Member] | Tax Year 2033 [Member]
Tax losses carried forward	2,877
State and Local Jurisdiction [Member] | Tax Year 2035 [Member]
Tax losses carried forward	4,394
State and Local Jurisdiction [Member] | Tax Year 2034 [Member]
Tax losses carried forward	3,565
State and Local Jurisdiction [Member] | Tax Year 2036 [Member]
Tax losses carried forward	6,366
State and Local Jurisdiction [Member] | Tax Year 2037 [Member]
Tax losses carried forward	396
State and Local Jurisdiction [Member] | Tax Year 2038 [Member]
Tax losses carried forward	13,811
State and Local Jurisdiction [Member] | Tax Year 2039 [Member]
Tax losses carried forward	32,356
State and Local Jurisdiction [Member] | Tax Year 2040 [Member]
Tax losses carried forward	23,421
State and Local Jurisdiction [Member] | Tax Year 2041 [Member]
Tax losses carried forward	13,988
State and Local Jurisdiction [Member] | Tax Year 2042 [Member]
Tax losses carried forward	10,910
United States [Member]
Tax losses carried forward	13,288
United States [Member] | No Expiry [Member]
Tax losses carried forward	$ 13,288