Marketable Securities - Summary of Marketable Securities (Details) - USD ($)	Oct. 31, 2015	Jan. 31, 2015
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 25,207,000
Unrealized Gain	3,000
Unrealized Loss	(6,000)
Estimated Fair Value	25,204,000	$ 0
Corporate Paper
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	3,094,000
Unrealized Gain	1,000
Estimated Fair Value	3,095,000
Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	15,869,000
Unrealized Gain	2,000
Unrealized Loss	(4,000)
Estimated Fair Value	15,867,000
Asset-backed Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	6,244,000
Unrealized Loss	(2,000)
Estimated Fair Value	$ 6,242,000