Correction of immaterial errors (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2016
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Error Corrections and Prior Period Adjustments, Description	An error was identified during the preparation and review of the second quarter, July 31, 2017, financial statements, as stock-based compensation cost and additional paid in capital had been reversed for vested equity awards that expired, terminated or were unexercised
Additional paid-in capital	$ 56,304	$ 55,358
Retained earnings	(3,103)	6,873
General and administrative expense	16,214	17,579
Total operating expenses	21,254	23,300
Loss from operations	(9,512)	(11,584)
Loss from continuing operations before income taxes	(10,209)	(13,773)
Loss from continuing operations	(9,976)	(13,162)
Net loss	$ (9,976)	$ (12,474)
Loss per share from continuing operations	$ (1.30)	$ (1.76)
Loss per share, basic and diluted	$ (1.30)	$ (1.67)
Stock-based compensation expense	$ 1,447	$ 1,446
Scenario, Previously Reported [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Additional paid-in capital		53,716
Retained earnings		8,515
General and administrative expense		16,783
Total operating expenses		22,504
Loss from operations		(10,788)
Loss from continuing operations before income taxes		(12,977)
Loss from continuing operations		(12,366)
Net loss		$ (11,678)
Loss per share from continuing operations		$ (1.65)
Loss per share, basic and diluted		$ (1.56)
Stock-based compensation expense		$ 650
Restatement Adjustment [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Additional paid-in capital		1,642
Retained earnings		(1,642)
General and administrative expense		796	$ (846)
Total operating expenses		796
Loss from operations		(796)
Loss from continuing operations before income taxes		(796)
Loss from continuing operations		(796)
Net loss		$ (796)
Loss per share from continuing operations		$ (0.11)
Loss per share, basic and diluted		$ (0.11)
Stock-based compensation expense		$ 796