Note 4 - Fair Value Measurements - Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Jul. 31, 2019	Jan. 31, 2019
Short-term investments	$ 1,200	$ 1,200
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Money market mutual funds	106,774	107,855
Short-term investments	1,200	1,200
Liability related to the interest rate swap
Asset related to the interest rate swap
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Money market mutual funds
Short-term investments
Liability related to the interest rate swap	$ (115)
Asset related to the interest rate swap		$ 136