Convertible Debt

12 Months Ended

Dec. 31, 2017

2015 Convertible Senior Notes

On February 17, 2015, the Company repaid at maturity the entire $18.0 million outstanding balance of the 4.5% convertible senior notes due 2015 (the "2015 convertible senior notes") in accordance with the terms thereof. No convertible senior notes were converted to common stock.

The following table outlines the effective interest rate, contractually stated interest costs, and costs related to the amortization of issuance costs for the Company's 2015 convertible senior notes:



	Years Ended
	December 31,
	2017	2016	2015
Effective interest rate of 2015 convertible senior notes	NA	NA	4.50%
Contractually stated interest costs	NA	NA	$101
Amortization of interest costs	NA	NA	$7