Note 3 - Computation of Net Income (Loss) Per Share - Computation of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2018	Jul. 31, 2017
Net income (loss)	$ 1,113	$ (1,161)	$ 2,510	$ (3,732)
Dividends declared	(1,372)	(1,344)	(2,731)	(2,675)
Undistributed net loss	(259)	(2,505)	(221)	(6,407)
Net (loss) income per share
Dividends declared	1,372	1,344	2,731	2,675
Undistributed net loss	(259)	(2,505)	(221)	(6,407)
Net income	1,113	(1,161)	2,510	(3,732)
Common Class A [Member]
Net income (loss)	954	(994)	2,150	(3,193)
Dividends declared	(1,176)	(1,151)	(2,340)	(2,290)
Undistributed net loss	(222)	(2,145)	(190)	(5,483)
Net (loss) income per share
Dividends declared	1,176	1,151	2,340	2,290
Undistributed net loss	(222)	(2,145)	(190)	(5,483)
Net income	$ 954	$ (994)	$ 2,150	$ (3,193)
Weighted average shares of common stock outstanding—basic (in shares)	16,266	15,914	16,173	15,863
Weighted average potential shares of common stock (in shares)	1,661		1,713
Weighted average shares of common stock and potential common shares outstanding—diluted (in shares)	17,927	15,914	17,886	15,863
Basic income per share (in dollars per share)	$ 0.06	$ (0.06)	$ 0.13	$ (0.20)
Diluted income per share (in dollars per share)	$ 0.05	$ (0.06)	$ 0.12	$ (0.20)
Common Class B [Member]
Net income (loss)	$ 159	$ (167)	$ 360	$ (539)
Dividends declared	(196)	(193)	(391)	(385)
Undistributed net loss	(37)	(360)	(31)	(924)
Net (loss) income per share
Dividends declared	196	193	391	385
Undistributed net loss	(37)	(360)	(31)	(924)
Net income	$ 159	$ (167)	$ 360	$ (539)
Weighted average shares of common stock outstanding—basic (in shares)	3,263	3,212	3,248	3,211
Weighted average potential shares of common stock (in shares)	171		177
Weighted average shares of common stock and potential common shares outstanding—diluted (in shares)	3,434	3,212	3,425	3,211
Basic income per share (in dollars per share)	$ 0.05	$ (0.05)	$ 0.11	$ (0.17)
Diluted income per share (in dollars per share)	$ 0.05	$ (0.05)	$ 0.11	$ (0.17)