Income Tax (Details Textual) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Income Tax (Textual) [Abstract]
Recognized federal research and development tax credits	$ 1,055	$ 927	$ 605
State research and development tax credits	165	119	129
Qualified production activities deduction under Section 199 of the Internal Revenue Code	10,025	8,134	4,133
Amount of unrecognized tax benefit that would decrease income tax provision if recognized	413
Accrued interest related to income tax	75	83
Penalties Accrued
Period within which the company does not anticipate total unrecognized tax benefits to change	within the next twelve months