Commitments and Contingencies (Details) (USD $)	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Future minimum lease payments under noncancelable operating leases
2013	$ 692,000
2014	708,000
2015	515,000
2016	125,000
2017 and thereafter	14,000
Total minimum lease payments	2,054,000
Rent expense	$ 805,000	$ 813,000	$ 766,000
Maximum duration of service warranties	30 days