Valuation and Qualifying Accounts (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012		Mar. 31, 2011
Allowance for doubtful accounts
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	$ 226	$ 346		$ 427
Additions Resulting in Charges to Operations	560	96		8
Charges to Other Accounts	284	63		35
Deductions Due to Write-Offs	(99)	(279)		(124)
Balance at End of Year	971	226		346
Deferred tax asset valuation allowance
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	3,529	249		249
Additions Resulting in Charges to Operations	101	0		0
Charges to Other Accounts	165	3,280	[1]	0
Deductions Due to Write-Offs	0	0		0
Balance at End of Year	$ 3,795	$ 3,529		$ 249

[1] Recorded in connection with the acquisition of Psytechnics.