DEBT (Tables)

6 Months Ended

Sep. 30, 2015

LONG-TERM DEBT

Information related to availability on Credit Agreement

	September 30, 2015		March 31, 2015
Available borrowings	$	98,336	$	98,335
Outstanding letters of credit		1,664		1,664

1.75% Convertible Notes due 2016

LONG-TERM DEBT

Schedule of additional information related to convertible notes

	September 30, 2015		March 31, 2015
Additional paid-in capital	$	51,180	$	51,180
Principal amount of 1.75% Convertible Notes	$	250,000	$	250,000
Unamortized discount of the liability component		13,795		19,386
Net carrying amount of 1.75% Convertible Notes	$	236,205	$	230,614
Carrying amount of debt issuance costs	$	1,154	$	1,662

Schedule of components of interest expense related to convertible notes

	Three Months Ended September 30,				Six Months Ended September 30,
	2015		2014		2015		2014
Cash interest expense (coupon interest expense)	$	1,093	$	1,094	$	2,187	$	2,188
Non-cash amortization of discount on 1.75% Convertible Notes		2,818		2,637		5,591		5,231
Amortization of debt issuance costs		252		265		508		533
Total interest expense related to 1.75% Convertible Notes	$	4,163	$	3,996	$	8,286	$	7,952

1.00% Convertible Notes due 2018

LONG-TERM DEBT

Schedule of additional information related to convertible notes

	September 30, 2015		March 31, 2015
Additional paid-in capital	$	35,784	$	35,784
Principal amount of 1.00% Convertible Notes	$	287,500	$	287,500
Unamortized discount of the liability component		36,104		42,057
Net carrying amount of 1.00% Convertible Notes	$	251,396	$	245,443
Carrying amount of debt issuance costs	$	1,141	$	1,365

Schedule of components of interest expense related to convertible notes

	Three Months Ended September 30,				Six Months Ended September 30,
	2015		2014		2015		2014
Cash interest expense (coupon interest expense)	$	718	$	718	$	1,437	$	1,437
Non-cash amortization of discount on 1.00% Convertible Notes		2,999		2,826		5,953		5,609
Amortization of debt issuance costs		112		117		224		236
Total interest expense related to 1.00% Convertible Notes	$	3,829	$	3,661	$	7,614	$	7,282