XML 39 R28.htm IDEA: XBRL DOCUMENT v3.10.0.1
Debt (Tables)
 6 Months Ended
Jun. 30, 2018
Debt Disclosure [Abstract]  
Summary of convertible notes
The Convertible Notes consist of the following:
Liability component
 
June 30, 2018
 
December 31, 2017
Principal
 
$
150,000

 
$
150,000

Less: Debt issuance costs
 
(1,939
)
 
(2,121
)
Less: Debt discount, net(1)
 
(38,929
)
 
(42,572
)
Net carrying amount
 
$
109,132

 
$
105,307

 
(1) Included in the consolidated balance sheets within convertible senior notes (due 2022) and amortized to interest expense over the remaining life of the Convertible Notes using the effective interest rate method.
Summary of interest expense recognized related to the Convertible Notes
The following table sets forth total interest expense recognized related to the Convertible Notes:
 
 
Three Months Ended June 30,
 
Six Months Ended June 30,
 
 
2018
 
2017
 
2018
 
2017
Contractual interest expense
 
$
1,131

 
$
1,131

 
$
2,241

 
$
2,241

Amortization of debt issuance costs
 
93

 
83

 
182

 
163

Amortization of debt discount
 
1,863

 
1,674

 
3,644

 
3,274

Total
 
$
3,087

 
$
2,888

 
$
6,067

 
$
5,678

Effective interest rate of the liability component
 
11
%
 
11
%
 
11
%
 
11
%