Summary of Significant Accounting Policies - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Mar. 31, 2014 Location	Mar. 31, 2013	Mar. 31, 2012
Property Plant And Equipment [Line Items]
Manufacturing facility located	1
Age of movement in inventory	5 years
Percentage of scrap on purchases	1.10%
Depreciation expense	$ 1,351	$ 1,392	$ 1,457
Expected net sale proceeds	3,800
Options to purchase shares	169,000	733,000	285,000
Warranty for the equipment	1 year
Engineering expense	8,162	9,377	12,531
Shipping and handling costs	266	202	194
Amount recognized in financial statement benefit of tax position	50.00%
Qualification Units
Property Plant And Equipment [Line Items]
Amortization of qualification units	339	73	243
Impairment of qualification units	399	106	3,165
Research and Development Costs
Property Plant And Equipment [Line Items]
Engineering expense	$ 6,916	$ 7,664	$ 14,702