Fair Value Measurement Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) (USD $) In Thousands, unless otherwise specified	Jan. 31, 2015	Jan. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Short-term investments	$ 0	$ 3,990
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Short-term investments		3,990
Contingent consideration	4,563	4,571
Fair Value, Net Asset (Liability)		(581)
Level 1 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Short-term investments		0
Contingent consideration	0	0
Fair Value, Net Asset (Liability)		0
Level 2 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Short-term investments		3,990
Contingent consideration	0	0
Fair Value, Net Asset (Liability)		3,990
Level 3 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Short-term investments		0
Contingent consideration	4,563	4,571
Fair Value, Net Asset (Liability)		$ (4,571)