Note 11 - Treasury Stock and Repurchase Program (Details Textual) - USD ($)		1 Months Ended		3 Months Ended				9 Months Ended		73 Months Ended
	Oct. 31, 2018	Jan. 30, 2012	Jan. 31, 2011	Jan. 31, 2019	Oct. 31, 2018	Jul. 31, 2018	[1]	Jan. 31, 2019	Jan. 31, 2018	Oct. 31, 2018	Oct. 19, 2018	Sep. 19, 2012
Treasury Stock, Shares, Acquired				13,438		2,286
Treasury Stock, Value, Acquired, Cost Method				$ 285,000		$ 46,000		$ 331,000	$ 191,000
October 2018 Share Repurchase Program [Member]
Stock Repurchase Program, Authorized Amount											$ 2,000,000
Treasury Stock, Shares, Acquired	13,438
Treasury Stock, Acquired, Total Average Cost	$ 285,000
Former Repurchase Program [Member]
Treasury Stock, Shares, Acquired		85,219
Treasury Stock, Value, Acquired, Cost Method		$ 1,036,000
January 2011 Share Repurchase Program [Member]
Treasury Stock, Shares, Acquired			18,400
September 2012 Share Repurchase Program [Member]
Stock Repurchase Program, Authorized Amount												$ 3,000,000
Treasury Stock, Shares, Acquired										207,047
Treasury Stock, Value, Acquired, Cost Method										$ 2,792,000

[1] Includes 207,047 shares with a total average cost of $2,792,000 that were acquired during the $3 million repurchase program which was authorized in September 2012 and expired in October 2018.