Goodwill & Other Intangibles - Gross carrying amount and related accumulated amortization of definite-lived intangible assets (Details) - USD ($) $ in Thousands	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Amount	$ 26,991	$ 26,655	$ 14,225
Accumulated Amortization	(11,159)	(8,165)	(6,069)
Net	15,832	18,490	8,156
Existing Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Amount	8,825	8,870	7,840
Accumulated Amortization	(6,487)	(5,239)	(4,164)
Net	2,338	3,631	3,676
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Amount	14,101	14,128	3,494
Accumulated Amortization	(2,794)	(1,271)	(525)
Net	11,307	12,857	2,969
Other Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Amount	4,065	3,657	2,891
Accumulated Amortization	(1,878)	(1,655)	(1,380)
Net	$ 2,187	$ 2,002	$ 1,511