Income Taxes - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2017	Oct. 31, 2016	Feb. 01, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Tax provision (benefit)	$ (940,000)	$ 91,000	$ (463,000)	$ 267,000
Loss before income taxes	$ 34,718,000	$ 21,840,000	$ 90,144,000	$ 65,018,000
Effective income tax rate	2.70%	(0.40%)	0.50%	(0.40%)
Tax benefit from stock-based compensation			$ 1,200,000
Accounting Standards Update 2016-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase of deferred tax assets					$ 300,000
Increase of deferred tax asset valuation allowance					300,000
Retained Earnings | Accounting Standards Update 2016-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative impact adjustment					$ 0