Statement of Earnings (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Income Statement [Abstract]
Net revenues	$ 368,004	$ 363,273	$ 243,224
Cost of goods sold	248,384	241,175	179,791
Gross profit	119,620	122,098	63,433
Operating expenses:
Research, development and engineering	27,930	27,527	20,112
Selling, general and administrative	43,356	42,881	36,163
Amortization of acquisition-related intangible assets	2,524	6,937	1,839
Restructuring charges	0	759	1,614
Impairment charges	6,448	702	0
Total operating expenses	80,258	78,806	59,728
Operating income	39,362	43,292	3,705
Other income (expense):
Interest income	367	285	426
Interest expense	(1,129)	(1,513)	(1,656)
Other income (expense), net	1,941	836	(141)
Income before income tax provision	40,541	42,900	2,334
Provision for income tax	(10,235)	(6,253)	(3,011)
Net income (loss)	$ 30,306	$ 36,647	$ (677)
Net income (loss) per share:
Basic	$ 0.97	$ 1.17	$ (0.02)
Diluted	$ 0.93	$ 1.14	$ (0.02)
Weighted average shares used in per share calculation:
Basic	31,344	31,235	31,005
Diluted	32,496	32,008	31,005