Income taxes Income taxes (Details) - USD ($)	3 Months Ended		9 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2016	Oct. 31, 2015
Income Tax Disclosure [Abstract]
effective income tax rate from continuing operations	(209.80%)	17.20%	(11.40%)	51.70%
Unrecognized tax benefits	$ 100,000		$ 100,000
Unrecognized tax benefits, income tax penalties and interest expense	1,500
Unrecognized tax benefits, income tax penalties and interest accrued	$ 48,700		$ 48,700
Income Tax Contingency [Line Items]
Income Tax Examination, Description			IRS began an audit of the fiscal year ended January 31, 2015