Other intangible assets with definite lives (Details) (USD $)	3 Months Ended		6 Months Ended
	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2014	Jul. 31, 2013	Jan. 31, 2014
Other intangible assets with definite lives [Abstract]
Gross patents	$ 2,630,000		$ 2,630,000		$ 2,600,000
Accumulated amortization	2,250,000		2,250,000		2,230,000
Amortization expense, next twelve months	25,600		25,600
Amortization expense, year two	48,000		48,000
Amortization expense, year three	44,200		44,200
Amortization expense, year four	41,200		41,200
Amortization expense, year five	32,200		32,200
Amortization expense, thereafter	187,900		187,900
Patent amortization expense	$ 12,000	$ 12,000	$ 25,000	$ 26,000