XML 38 R27.htm IDEA: XBRL DOCUMENT v3.8.0.1
Debt (Tables)
 3 Months Ended
Mar. 31, 2018
Debt Disclosure [Abstract]  
Summary of convertible notes
The Convertible Notes consist of the following:
Liability component
 
March 31, 2018
 
December 31, 2017
Principal
 
$
150,000

 
$
150,000

Less: Debt issuance costs
 
(2,032
)
 
(2,121
)
Less: Debt discount, net(1)
 
(40,791
)
 
(42,572
)
Net carrying amount
 
$
107,177

 
$
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 March 31,
 
 
 
2018
 
2017
 
Contractual interest expense
 
$
1,110

 
$
1,110

 
Amortization of debt issuance costs
 
89

 
80

 
Amortization of debt discount
 
1,780

 
1,600

 
Total
 
$
2,979

 
$
2,790

 
Effective interest rate of the liability component
 
11
%
 
11
%