XML 48 R28.htm IDEA: XBRL DOCUMENT v3.19.1
Share-Based Compensation (Tables)
 12 Months Ended
Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]  
Schedule of fair value assumptions
The fair value of the SARs is estimated at each financial reporting date using the Black-Scholes option-pricing model, using the following assumptions:
 
December 31, 2018
Estimated dividend yield
—

Expected volatility
86.71
%
Risk-free interest rate
2.63
%
Expected term (years)
1.09

Fair value per share of common stock underlying the SAR
$
0.83

SAR exercise price
$
3.80

The fair value of each option grant is estimated on the grant date using the Black-Scholes option-pricing model, and the following weighted average assumptions:
 
Year Ended December 31,
 
2018
 
2017
Estimated dividend yield
0.00
%
 
0.00
%
Expected volatility
81.73
%
 
82.16
%
Risk-free interest rate
2.75
%
 
1.81
%
Expected life of options (in years)
5.68

 
5.04

Weighted-average fair value per share
$
2.06

 
$
3.31

The fair value of the Performance Plan is estimated at each financial reporting date using the Monte Carlo simulation model and the following assumptions:
 
December 31, 2018
Estimated dividend yield
—

Expected volatility
87.19
%
Risk-free interest rate
2.47
%
Expected term (years)
3.17

Fair value per share of common stock underlying the Performance Plan
$
0.83
Schedule of Share-based Compensation Expenses
Total share-based compensation expense included in the consolidated statements of operations is as follows:
 
Year Ended December 31,
 
2018
 
2017
Research and development
$
1,144

 
$
1,768

General and administrative
1,060

 
1,990

 
$
2,204

 
$
3,758
Summary of Stock Option Activity
Stock option activity for the periods indicated is as follows:
 
Shares
Available
for Grant
 
Shares
Subject to
Outstanding
Options
 
Weighted-
Average
Exercise
Price Per
Share
 
Weighted-
Average
Remaining
Contractual
Term (in years)
 
Aggregate
Intrinsic
Value
Options outstanding as of December 31, 2016
615,207

 
825,130

 
$
11.27

 
 
 
 
Additional shares reserved under plan
1,200,000

 
—

 
 
 
 
 
 
Options granted
(926,195
)
 
926,195

 
5.15

 
 
 
 
Options forfeited
134,366

 
(286,425
)
 
13.81

 
 
 
 
Options exercised
—

 
(65,416
)
 
1.25

 
 
 
 
Options outstanding as of December 31, 2017
1,023,378

 
1,399,484

 
$
7.17

 
 
 
 
Options granted
(626,757
)
 
727,257

 
2.97

 
 
 
 
Options forfeited
302,755

 
(403,748
)
 
7.61

 
 
 
 
Options exercised
—

 
(51,327
)
 
1.16

 
 
 
 
Options outstanding as of December 31, 2018
699,376

 
1,671,666

 
$
5.42

 
8.17
 
$
2

Vested and expected to vest as of
   December 31, 2017
 
 
1,319,798

 
$
7.23

 
8.77
 
$
390

Exercisable as of December 31, 2017
 
 
678,480

 
$
7.76

 
8.24
 
$
366

Vested and expected to vest as of
   December 31, 2018
 
 
1,585,689

 
$
5.53

 
8.11
 
$
2

Exercisable as of December 31, 2018
 
 
1,007,870

 
$
6.58

 
7.54
 
$
2