Stock-based Compensation (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Stock options
Major components of stock based compensation expense
Stock-based compensation expense	$ 295	$ 484
Exercised (in shares)	6	21
Stock options | Cost of sales
Major components of stock based compensation expense
Stock-based compensation expense	138	212
Stock options | Selling, general and administrative expenses
Major components of stock based compensation expense
Stock-based compensation expense	147	254
Stock options | Research and development
Major components of stock based compensation expense
Stock-based compensation expense	10	18
Restricted stock
Major components of stock based compensation expense
Stock-based compensation expense	296	519
Restricted stock | Cost of sales
Major components of stock based compensation expense
Stock-based compensation expense	63	121
Restricted stock | Selling, general and administrative expenses
Major components of stock based compensation expense
Stock-based compensation expense	233	398
LTIP Plans
Stock-based Compensation
Performance period	2 years
Major components of stock based compensation expense
Stock-based compensation expense	377	261
LTIP Plans | Cost of sales
Major components of stock based compensation expense
Stock-based compensation expense	114	68
LTIP Plans | Selling, general and administrative expenses
Major components of stock based compensation expense
Stock-based compensation expense	214	173
LTIP Plans | Research and development
Major components of stock based compensation expense
Stock-based compensation expense	$ 49	$ 20
2013/2014 LTIP | Restricted stock
Stock-based compensation, additional disclosure
Vesting period	3 years
2014/2015 LTIP | Restricted stock
Stock-based compensation, additional disclosure
Vesting period	3 years