Share-Based Compensation (Tables)
 3 Months Ended
Apr. 30, 2016
Share-based Compensation [Abstract]  
Schedule of Shared-based Compensation Expense
The following summarizes share-based compensation expense:
 
Thirteen Weeks Ended
 
April 30, 2016
 
May 2, 2015
 
(in thousands)
Restricted stock units and restricted stock
$
3,305

 
$
2,607

Stock options
1,063

 
1,244

Total share-based compensation
$
4,368

 
$
3,851
Schedule of Share-based Compensation, Activity
The Company's activity with respect to stock options during the thirteen weeks ended April 30, 2016 was as follows:
 
Number of
Shares 
 
Grant Date
Weighted Average
Exercise Price Per Share
 
Weighted-Average Remaining Contractual Life (in years)
 
Aggregate Intrinsic Value
 
(in thousands, except per share amounts and years)
Outstanding, January 31, 2016
3,446

 
$
18.31

 
 
 
 
Granted
229

 
$
21.14

 
 
 
 
Exercised
(156
)
 
$
17.35

 
 
 
 
Forfeited or expired
(29
)
 
$
20.13

 
 
 
 
Outstanding, April 30, 2016
3,490

 
$
18.52

 
6.0
 
$
2,793

Expected to vest at April 30, 2016
632

 
$
17.96

 
8.6
 
$
804

Exercisable at April 30, 2016
2,820

 
$
18.63

 
5.4
 
$
1,962
Supplemental Options Data
The following table provides additional information regarding the Company's stock options:
 
Thirteen Weeks Ended
 
April 30, 2016

May 2, 2015
 
(in thousands, except per share amounts)
Weighted average grant date fair value of options granted (per share)
$
9.50

 
$
7.76

Total intrinsic value of options exercised
$
536

 
$
—
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions
The fair value of stock options was estimated at the grant date using the Black-Scholes-Merton option pricing model with the following weighted-average assumptions:
 
Thirteen Weeks Ended
 
April 30, 2016
 
May 2, 2015
Risk-free interest rate (1)
1.60
%
 
1.59
%
Price volatility (2)
43.15
%
 
47.93
%
Expected term (years) (3)
6.54

 
6.25

Dividend yield (4)
—

 
—


(1)
Represents the yield on U.S. Treasury securities with a term consistent with the expected term of the stock options.
(2)
For the first two years following the initial public offering of the Company's common stock, this was based on the historical volatility of selected comparable companies over a period consistent with the expected term of the stock options because the Company had a limited history of being publicly traded. Comparable companies were selected primarily based on industry, stage of life cycle, and size. Beginning in May 2012, the Company began using its own volatility as an additional input in the determination of expected volatility.
(3)
Beginning in 2016, the Company calculated the expected term assumption using the midpoint scenario, which combines historical exercise data with hypothetical exercise data for outstanding options, as the Company believes this data currently represents the best estimate of the expected term of new employee options.
(4)
The Company does not currently plan on paying regular dividends.
Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity
The Company's activity with respect to RSUs and restricted stock, including awards with performance conditions, for the thirteen weeks ended April 30, 2016 was as follows:
 
Number of
Shares 
Grant Date
Weighted Average
Fair Value Per Share
 
(in thousands, except per share amounts)
Unvested, January 31, 2016
2,212

$
16.66

Granted (1)
926

$
21.14

Vested
(713
)
$
17.22

Forfeited
(105
)
$
17.44

Unvested, April 30, 2016
2,320

$
18.24


(1)
Approximately 0.3 million RSUs with three-year performance conditions are included in this amount, which represents 100% of the number of shares granted. This is based on current estimates against predefined financial performance targets ranging from 0% to 200%.