XML 98 R35.htm IDEA: XBRL DOCUMENT v3.8.0.1
STOCK-BASED COMPENSATION - (Tables)
 12 Months Ended
Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]  
Schedule of stock-based compensation expense
The following table summarizes the stock-based compensation expense by financial statement line item and type of award:
 
 
Year Ended 
 December 31,
 
 
2017
 
2016
 
2015
Cost of revenue
 
$
133

 
$
168

 
$
705

Research and development
 
264

 
532

 
844

Sales and marketing
 
1,197

 
1,581

 
4,045

General and administrative
 
4,338

 
4,675

 
5,594

 
 
$
5,932

 
$
6,956

 
$
11,188

 
 
 
Year Ended 
 December 31,
 
 
2017
 
2016
 
2015
Stock options
 
$
3,109

 
$
2,985

 
$
5,116

Restricted stock
 
1,952

 
1,052

 
313

Restricted stock units
 
570

 
2,527

 
5,460

ESPP
 
301

 
392

 
299

    Total
 
$
5,932

 
$
6,956

 
$
11,188
Schedule of employee stock option plan activity
Stock Options
The following table summarizes stock option plans activity:
 
 
Shares
 
Weighted-
Average
Exercise
Price
 
Weighted-
Average
Remaining
Contractual
Term
(years)
 
Aggregate
Intrinsic
Value (1)
Outstanding at December 31, 2016 (2)
 
3,685,125

 
$
12.45

 
6.05
 
$
29,142

Granted
 
414,507

 
22.67

 

 

Exercised
 
(842,704
)
 
10.25

 

 

Expired
 
(4,904
)
 
8.03

 

 

Forfeited
 
(86,637
)
 
17.23

 

 

Outstanding at December 31, 2017 
 
3,165,387

 
$
14.26

 
5.88
 
$
15,567

Vested:
 
 
 
 
 
 
 
 
At December 31, 2017
 
2,331,801

 
$
12.29

 
4.84
 
$
13,939

Expected to vest:
 
 
 
 
 
 
 
 
At December 31, 2017
 
833,586

 
$
19.76

 
1.86
 
$
1,087


(1)
Calculated using the fair market value per share of our common stock as of December 31, 2017 and 2016 of $18.00 and $20.04, respectively.
(2)
The total includes 980,671 performance-based options at December 31, 2016.

Schedule of stock option valuation assumptions
The fair value was determined by applying the Black-Scholes-Merton option pricing model, utilizing the following weighted-average assumptions:
 
 
Year Ended 
 December 31,
 
 
2017
 
2016
 
2015
Expected dividend yield
 
—
%
 
—
%
 
—
%
Expected volatility
 
34.05-35.42

 
34.16-36.54

 
36.31-41.33

Risk-free interest rate
 
1.89-2.18

 
1.20-1.64

 
1.42-2.18

Expected average life of options
 
6.5 years

 
6-7 years

 
7 years
Schedule of Restricted Stock Units Activity
The weighted average grant date fair values of restricted stock and RSUs granted to employees during the years ended December 31, 2017, 2016 and 2015 is as follows:
 
 
Year Ended 
 December 31,
 
 
2017
 
2016
 
2015
Weighted-average grant date fair value per share - restricted stock
 
$
22.81

 
$
14.38

 
$
23.46

Weighted-average grant date fair value per share or unit - RSUs
 
$
21.63

 
$
16.05

 
$
—

A summary of restricted stock and RSU activity during the year ended December 31, 2017 is as follows:
 
 
Restricted Stock
 
Restricted Stock Units
 
 
Number of Shares
 
Weighted-Average Grant Date Fair Value
 
Weighted-Average Remaining Term (years)
 
Number of Shares
 
Weighted-Average Grant Date Fair Value
 
Weighted-Average Remaining Term (years)
Non-vested at December 31, 2016
 
218,505

 
$
16.59

 
2.35
 
79,457

 
$
15.22

 
0.81
    Vested
 
(80,384
)
 
$
17.39

 

 
(68,464
)
 
$
15.08

 

    Granted
 
131,562

 
$
22.81

 

 
35,254

 
$
21.63

 

    Forfeited
 
(3,999
)
 
$
14.38

 

 
—

 
$
—

 

Non-vested at December 31, 2017
 
265,684

 
$
19.46

 
2.03
 
46,247

 
$
15.83

 
2.28
Vested or expected to vest:
 
 
 
 
 
 
 
 
 
 
 
 
    At December 31, 2017
 
265,684

 
$
19.46

 
2.03
 
46,247

 
$
15.83

 
2.28