Goodwil, Long-lived Assets, and Other Charges - Gross carrying amount and related accumulated amortization of definite-lived intangible assets (Details) - USD ($) $ in Thousands	Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Amount	$ 24,501	$ 23,739	$ 26,655
Accumulated Amortization	(12,453)	(10,783)	(8,165)
Net	12,048	12,956	18,490
Existing Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Amount	7,136	7,144	8,870
Accumulated Amortization	(6,553)	(6,265)	(5,239)
Net	583	879	3,631
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Amount	12,987	12,628	14,128
Accumulated Amortization	(3,680)	(2,641)	(1,271)
Net	9,307	9,987	12,857
Patented Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Amount	4,378	3,967	3,657
Accumulated Amortization	(2,220)	(1,877)	(1,655)
Net	$ 2,158	$ 2,090	$ 2,002