Leases - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jul. 31, 2019	Jul. 31, 2019	Apr. 30, 2019	Feb. 01, 2019
Leases [Abstract]
Operating lease right-of-use assets	$ 2,738	$ 2,738	$ 3,014	$ 2,710
Total operating lease liabilities	2,738	2,738	$ 3,014	$ 2,710
Operating lease expense	290	590
Short-term lease costs	$ 10	$ 20