DEBT (Tables)

3 Months Ended

Jun. 30, 2013

DEBT

Information related to availability on Credit Agreement

	June 30, 2013		March 31, 2013
Available borrowings	$	71,863	$	73,565
Outstanding letters of credit		1,664		1,664

4.375% convertible notes due 2014

LONG-TERM DEBT

Information about carrying amount and components of interest expense of convertible notes

	June 30, 2013		March 31, 2013
Additional paid-in capital	$	42,018	$	42,018
Principal amount of 4.375% Convertible Notes	$	138,000	$	138,000
Unamortized discount of the liability component		10,232		12,819
Current net carrying amount of 4.375% Convertible Notes	$	127,768	$	—
Non-current net carrying amount of 4.375% Convertible Notes	$	—	$	125,181
Carrying amount of debt issuance costs	$	626	$	797

	Three Months Ended June 30,
	2013		2012
Cash interest expense (coupon interest expense)	$	1,509	$	1,509
Non-cash amortization of discount on 4.375% Convertible Notes		2,587		2,273
Amortization of debt issuance costs		171		171
Total interest expense related to 4.375% Convertible Notes	$	4,267	$	3,953

1.75% Convertible Notes due 2016

LONG-TERM DEBT

Information about carrying amount and components of interest expense of convertible notes

	June 30, 2013		March 31, 2013
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		37,552		39,979
Net carrying amount of 1.75% Convertible Notes	$	212,448	$	210,021
Carrying amount of debt issuance costs	$	3,540	$	3,821

	Three Months Ended June 30,
	2013		2012
Cash interest expense (coupon interest expense)	$	1,094	$	1,094
Non-cash amortization of discount on 1.75% Convertible Notes		2,427		2,270
Amortization of debt issuance costs		281		295
Total interest expense related to 1.75% Convertible Notes	$	3,802	$	3,659

1.00% Convertible Notes due 2018

LONG-TERM DEBT

Information about carrying amount and components of interest expense of convertible notes

	June 30, 2013
Additional paid-in capital	$	50,105
Principal amount of 1.00% Convertible Notes	$	250,000
Unamortized discount of the liability component		53,523
Net carrying amount of 1.00% Convertible Notes	$	196,477
Carrying amount of debt issuance costs	$	1,914

	Three Months Ended June 30, 2013
Cash interest expense (coupon interest expense)	$	90
Non-cash amortization of discount on 1.00% Convertible Notes		332
Amortization of debt issuance costs		12
Total interest expense related to 1.00% Convertible Notes	$	434