Annual report pursuant to Section 13 and 15(d)

Stock-based Expense (Tables)

v3.8.0.1
Stock-based Expense (Tables)
12 Months Ended
Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]  
Summary of Stock Option Transactions Under Equity Plan, Stock Incentive Plan, Multifamily Technology Solutions Plan and Board Plan
The following table summarizes stock option transactions under our Stock Incentive Plan, Equity Incentive Plan, Board Plan, and MTS Plan:
 
 
Number of Shares
 
Range of
Exercise Prices
 
Weighted Average
Exercise Price
Balance as of January 1, 2015
 
5,566,888

 
$
0.91

$
29.50

 
$
18.89

Granted
 
2,434,198

 
18.79

23.10

 
19.81

Exercised
 
(809,303
)
 
0.91

21.60

 
14.97

Forfeited/cancelled
 
(1,389,910
)
 
5.04

29.50

 
20.54

Balance at December 31, 2015
 
5,801,873

 
0.91

29.50

 
19.43

Exercised
 
(1,568,699
)
 
1.68

27.18

 
18.16

Forfeited/cancelled
 
(625,431
)
 
4.28

29.50

 
21.77

Expired
 
(654
)
 
0.91

0.91

 
0.91

Balance at December 31, 2016
 
3,607,089

 
2.55

29.50

 
19.58

Exercised
 
(1,344,569
)
 
5.04

29.50

 
20.09

Forfeited/cancelled
 
(61,892
)
 
15.19

25.70

 
19.66

Expired
 
(163
)
 
2.55

2.82

 
2.73

Balance at December 31, 2017
 
2,200,465

 
4.28

29.50

 
19.26

Outstanding Stock Options, Vested and Expected to Vest, Non-Vested and Stock Options Currently Exercisable
The below table provides information regarding outstanding stock options which were fully vested and expected to vest and exercisable options at December 31:
 
 
2017
 
2016
 
 
Options Fully Vested and Expected to Vest
 
Options Exercisable
 
Options Fully Vested and Expected to Vest
 
Options Exercisable
Number of options
 
2,200,465

 
1,999,278

 
3,606,462

 
2,477,474

Weighted-average remaining contractual term (in years)
 
5.5

 
5.3

 
6.5

 
5.9

Weighted-average exercise price
 
$
19.26

 
$
19.16

 
$
19.58

 
$
19.24

Aggregate intrinsic value, in thousands
 
$
55,106

 
$
50,257

 
$
37,581

 
$
26,659

Awards Granted Assumptions
The fair value of each stock option grant was estimated as of the date of grant using the Black Scholes option-pricing model with the following weighted-average assumptions and resulting weighted-average fair value per share for the year ended December 31, 2015. There were no stock options awarded during the years ended December 31, 2017 and 2016.
 
2015
Risk-free interest rate
1.5
%
Expected option life (in years)
4.6

Expected volatility
42.3
%
Weighted-average grant date fair value
$
7.42

Summary of Time-Based Restricted Share Awards' Activity
A summary of time-based restricted stock award activity is presented in the table below.
 
 
Number of
Shares
 
Weighted
Average Grant-Date Fair Value
Non-vested shares at January 1, 2015
 
1,624,519

 
$
20.01

Granted
 
913,077

 
19.84

Vested
 
(1,077,102
)
 
19.78

Forfeited/cancelled
 
(391,788
)
 
18.65

Non-vested shares at December 31, 2015
 
1,068,706

 
20.05

Granted
 
1,793,257

 
20.79

Vested
 
(841,983
)
 
20.14

Forfeited/cancelled
 
(386,479
)
 
20.21

Non-vested shares at December 31, 2016
 
1,633,501

 
20.78

Granted
 
1,359,578

 
36.25

Vested
 
(953,749
)
 
23.73

Forfeited/cancelled
 
(283,342
)
 
28.01

Non-vested shares at December 31, 2017
 
1,755,988

 
30.05

Market Based Restricted Stock Units Activity
A summary of market-based restricted stock award activity is presented in the table below.
 
 
Number of
Shares
 
Weighted
Average Grant-Date Fair Value
Balance as of January 1, 2015
 
520,000

 
$
11.26

Granted
 
691,165

 
11.59

Forfeited/cancelled
 
(196,070
)
 
9.39

Balance at December 31, 2015
 
1,015,095

 
11.85

Granted
 
794,025

 
13.58

Vested
 
(51,250
)
 
12.52

Forfeited/cancelled
 
(193,710
)
 
11.61

Balance at December 31, 2016
 
1,564,160

 
12.73

Granted
 
535,441

 
28.18

Vested
 
(1,407,133
)
 
13.69

Forfeited/cancelled
 
(2,303
)
 
13.34

Balance at December 31, 2017
 
690,165

 
22.76

Restricted Stock Unit Valuation Assumptions
The weighted average of assumptions used to value awards granted during 2017, 2016, and 2015 were as follows:
 
 
2017
 
2016
 
2015
Risk-free interest rate
 
1.8
%
 
1.1
%
 
1.1
%
Expected volatility
 
31.6
%
 
41.5
%
 
38.7
%
Performance-Based Restricted Share Awards' Activity
A summary of performance-based restricted stock award activity is presented in the table below:
 
 
Number of
Shares
 
Weighted
Average Grant-Date Fair Value
Non-vested shares at January 1, 2015
 

 
$

Granted
 
20,000

 
18.79

Non-vested shares at December 31, 2015
 
20,000

 
18.79

Forfeited/cancelled
 
(20,000
)
 
18.79

Non-vested shares at December 31, 2016
 

 

Granted
 

 

Non-vested shares at December 31, 2017