XML 43 R29.htm IDEA: XBRL DOCUMENT v3.20.1
Stock-Based Compensation (Tables)
3 Months Ended
Mar. 31, 2020
Share-based Payment Arrangement [Abstract]  
Summary of Option Activity Plan
A summary of option activity under the Plans for the three months ended March 31, 2020 follows:
 
2006 and 2016 Plans 
(in thousands, except for share and per share amounts)
Number of
Shares
 
Weighted Average
Exercise Price at
Grant Date
 
Weighted Average
Remaining Term
(Years)
 
Aggregate
Intrinsic
Value
Outstanding at December 31, 2019
4,495,145

 
$
12.21

 
5.58
 
$
21,148

Granted
487,500

 
11.42

 
 
 
 
Forfeited
(225,000
)
 
18.83

 
 
 
 
Expired
(10,104
)
 
11.78

 
 
 
 
Exercised
(172,500
)
 
4.96

 
 
 
890

Outstanding at March 31, 2020
4,575,041

 
12.07

 
5.81
 
4,818

Exercisable at March 31, 2020
3,379,139

 
11.02

 
4.63
 
4,818

Vested and expected to vest at March 31, 2020
4,340,916

 
11.99

 
5.60
 
4,818


Summary of RSU Activity for 2006 Plan and 2016 Plan
A summary of RSU activity under the Plans for the three months ended March 31, 2020 follows:

2006 and 2016 Plans
Number of
Shares
Underlying RSUs
 
Weighted
Average
Grant Date Fair Value
Unvested at December 31, 2019
1,649,285

 
$
18.04

Granted
745,818

 
11.32

Forfeited
(136,091
)
 
18.65

Vested
(498,505
)
 
16.73

Unvested at March 31, 2020
1,760,507

 
15.52


Stock-Based Compensation Expense
Stock-based compensation expense recognized for the three months ended March 31, 2020 and 2019 was comprised of the following:
 
 
Three Months Ended
(in thousands)
March 31,
2020
 
March 31,
2019
Research and development
$
1,111

 
$
728

Selling, general and administrative
2,833

 
2,554

Total stock-based compensation expense
$
3,944

 
$
3,282


Black-Scholes-Merton Option Pricing Model for Employee and Director Stock Options Granted Assumptions used in the Black-Scholes-Merton option pricing model for employee and director stock options granted during the three months ended March 31, 2020 and 2019 were as follows:
 
 
Three Months Ended
 
March 31,
2020
 
March 31,
2019
Expected dividend yield
0
%
 
0
%
Weighted average expected volatility
52
%
 
58
%
Weighted average expected term (years)
6.09

 
5.92

Weighted average risk-free rate
1.37
%
 
2.51
%