CONVERTIBLE NOTES (Tables)

12 Months Ended

Dec. 31, 2014

CONVERTIBLE NOTES [Abstract]

Schedule of Interest Expense Recognized

The following table sets forth total interest expense recognized for the years ended December 31, 2013 and 2014 related to the Notes:

	Year ended December 31,
(U.S. Dollars in thousands)	2013		2014
Contractual interest expense	$	888	$	3,105
Amortization of debt issuance costs and debt discount		127		444
Total	$	1,015	$	3,549