Note 4 - Income Taxes - Net Operating Losses and Tax Credits (Details) $ in Thousands	Jan. 31, 2021 USD ($)
Credit Carryforwards	$ 24,312
Foreign Tax Credit [Member]
Credit Carryforwards	6,338
Research Tax Credit Carryforward [Member] | Domestic Tax Authority [Member]
Credit Carryforwards	8,336
Research Tax Credit Carryforward [Member] | State and Local Jurisdiction [Member]
Credit Carryforwards	9,380
AMT credit and New hire retention [Member]
Credit Carryforwards	$ 258