Revenue Recognition (Details)	3 Months Ended	9 Months Ended
Oct. 31, 2018 Rate	Oct. 31, 2017 Rate	Oct. 31, 2018 Rate	Oct. 31, 2017 Rate
Apple
Concentration Risk
Concentration Risk, Percentage	17.00%	18.00%	15.00%	16.00%
HP, Inc.
Concentration Risk
Concentration Risk, Percentage	11.00%	11.00%	11.00%	11.00%
Cisco Systems, Inc.
Concentration Risk
Concentration Risk, Percentage	10.00%	11.00%	11.00%	11.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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