Accrued Expenses (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Mar. 31, 2012
Schedule of Accrued Liabilities [Line Items]
Employee compensation	$ 8,365	$ 9,272
Sales and income taxes	1,871	948
Professional, accounting and auditing fees	1,160	427
Warranty	920	726
Research and development	863	519
Other	704	588
Accrued expenses	$ 13,883	$ 12,480