Employee Retirement Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2018	Jan. 31, 2017
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
Matching contribution percent (up to)	100.00%
Maximum contribution as a percent of participant compensation	4.00%
Defined contribution plan, cost recognized	$ 524	$ 541