XML 37 R37.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Stock-based Compensation (Tables)
 12 Months Ended
Dec. 31, 2019
Share-based Payment Arrangement [Abstract]  
Stock Option Activity and Related Information
A summary of the Company’s stock option activity under the Plans is as follows:
 
Shares
 
Weighted-
average exercise
price per share
 
Weighted-
average remaining
contractual
term (in years)
 
Aggregate
intrinsic value
(in thousands)
Outstanding at January 1, 2019
5,042,352

 
$
12.46

 
6.49
 
$
18,255

Granted
835,376

 
23.98

 
 
 
 
Canceled and forfeited
(269,421
)
 
14.90

 
 
 
 
Exercised
(1,416,185
)
 
13.82

 
 
 
 
Outstanding at December 31, 2019
4,192,122

 
$
14.42

 
6.47
 
$
56,218

 
 
 
 
 
 
 
 
December 31, 2019:
 
 
 
 
 
 
 
Options vested and expected to vest
4,192,122

 
$
14.42

 
6.47
 
$
56,218

Options exercisable
2,792,940

 
$
12.61

 
5.38
 
$
42,482
Company's Options Outstanding
The following table summarizes information about the Company’s stock options outstanding at December 31, 2019: 
 
Outstanding
 
Exercisable
Exercise Price
Number of
Shares
 
Weighted-
Average
Remaining
Contractual
Life in Years
 
Number of
Shares
 
Weighted-
Average
Remaining
Contractual
Life in Years
$1.92
309,208

 
2.22
 
309,208

 
2.22
$2.24 – $6.72
187,205

 
1.95
 
186,227

 
1.92
$6.80 – $12.56
857,753

 
7.14
 
485,456

 
6.40
$12.77
324,905

 
5.11
 
324,905

 
5.11
$12.89 – $12.94
297,516

 
6.17
 
276,318

 
6.13
$13.01 – $14.95
227,294

 
6.47
 
184,704

 
6.05
$14.99 – $17.48
319,666

 
6.55
 
248,011

 
6.18
$17.83 – $18.90
729,182

 
6.04
 
568,562

 
5.64
$19.09 – $22.71
252,012

 
8.11
 
109,271

 
6.73
$23.00 – $29.13
687,381

 
9.35
 
100,278

 
9.24
 
4,192,122




2,792,940

 
 
Restricted Stock Units Award Activity
A summary of RSU activity under the Plans is as follows:
Non-vested RSUs
 
Share Equivalent
 
Weighted-Average Grant Date Fair Value
Non-vested at January 1, 2019
 
1,141,129

 
$
8.68

Changes during the year:
 
 
 
 
Granted
 
1,087,691

 
23.33

Vested
 
(665,007
)
 
9.25

Forfeited
 
(128,039
)
 
18.04

Non-vested at December 31, 2019
 
1,435,774

 
$
18.69
Stock Compensation Expense
The following table sets forth stock-based compensation expense related to stock-based arrangements under the Plans for the years ended December 31 as follows (in thousands):
 
2019
 
2018
 
2017
Cost of revenue
$
786

 
$
616

 
$
719

Research and development
4,100

 
3,156

 
2,853

Selling, general and administrative
11,726

 
6,982

 
7,047

Total stock-based compensation expense
$
16,612


$
10,754


$
10,619
Fair Value of Employee Option Grant
The fair value of each employee option grant as of December 31 was estimated on the date of grant using the Black-Scholes option pricing model with the following assumptions:
 
2019
 
2018
 
2017
Risk-free interest rates
1.41% - 2.56%
 
2.22% - 3.01%
 
1.40% - 2.26%
Expected term (years)
5.12 - 6.08
 
5.50 - 6.09
 
5.50 - 6.25
Expected dividend yield
—
 
—
 
—
Expected volatility
52.6% - 58.02%
 
56.0% - 57.7%
 
53.9% - 58.0%