Basis of Financial Statement Presentation (Details) Share data in Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2012 USD ($)	Dec. 31, 2011	Dec. 31, 2012 USD ($)	Dec. 31, 2011	Mar. 31, 2012 USD ($)	Aug. 31, 2006 USD ($)	Aug. 31, 2006 EUR (€)	Dec. 31, 2012 Carrying Value USD ($)	Mar. 31, 2012 Carrying Value USD ($)	Dec. 31, 2012 Recurring USD ($)	Mar. 31, 2012 Recurring USD ($)	Dec. 31, 2012 Recurring Level 1 USD ($)	Mar. 31, 2012 Recurring Level 1 USD ($)	Dec. 31, 2012 Recurring Level 2 USD ($)	Mar. 31, 2012 Recurring Level 2 USD ($)
Restricted Cash
Prepayment received from an original equipment manufacturer (OEM)			$ 24,000,000
Guarantee issued by the European bank in conjunction with the establishment of a VAT registration in The Netherlands						2,000,000	1,500,000
Deposits pledged to the European bank						2,200,000	1,700,000
Fair Value Measurement
Money markets								26,253,000	26,215,000	26,253,000	26,215,000	26,253,000	26,215,000
Long-term debt								383,495,000	347,331,000	373,366,000	362,086,000	348,788,000	358,700,000	24,578,000	3,386,000
Revenue Recognition
Period of product warranty			1 year
Warranty costs as a percentage of net sales, maximum	1.00%	1.00%	1.00%	1.00%
Components of inventories
Raw materials and supplies	94,669,000		94,669,000		86,845,000
Work in process	72,708,000		72,708,000		72,411,000
Finished goods	73,073,000		73,073,000		70,122,000
Inventory, gross	240,450,000		240,450,000		229,378,000
Inventory reserves	(19,090,000)		(19,090,000)		(17,144,000)
Inventories, net	$ 221,360,000		$ 221,360,000		$ 212,234,000
Warrant Liability
Number of shares subject to a warrant held by K Equity, LLC	8.4		8.4		8.4