Debt (Details) - USD ($)				3 Months Ended
	Apr. 28, 2017	Nov. 18, 2016	Mar. 16, 2016	Apr. 30, 2017	Apr. 30, 2016	Jan. 31, 2017
Line of Credit Facility [Line Items]
Repayments of line of credit				$ 5,000,000	$ 0
Long-term debt				$ 0
Revolving Credit Line
Line of Credit Facility [Line Items]
Proceeds from line of credit		$ 5,000,000
Repayments of line of credit	$ 5,000,000
Line of Credit | Revolving Credit Line
Line of Credit Facility [Line Items]
Long-term debt						$ 5,000,000
Line of Credit | Silicon Valley Bank
Line of Credit Facility [Line Items]
Debt issuance costs			$ 0
Covenant terms, minimum adjusted quick ratio			1.25
Line of Credit | Silicon Valley Bank | Revolving Credit Line
Line of Credit Facility [Line Items]
Borrowing capacity			$ 15,000,000
Commitment fee, percentage			0.25%
Line of Credit | Silicon Valley Bank | Letter of Credit
Line of Credit Facility [Line Items]
Borrowing capacity			$ 7,000,000
Commitment fee, percentage			1.75%
Line of Credit | Prime Rate | Silicon Valley Bank | Revolving Credit Line
Line of Credit Facility [Line Items]
Basis spread on variable rate			0.50%