Condensed Consolidated Statements of Income and Comprehensive Income (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Jul. 31, 2012	Jul. 31, 2011
Net revenues	$ 16,685	$ 15,939
Cost of revenues	10,704	9,795
Gross margin	5,981	6,144
Selling and administrative expenses	3,485	3,162
Research and development expense	1,415	1,198
Operating profit	1,081	1,784
Other income (expense):
Investment income	167	125
Equity income		19
Interest expense	(56)	(24)
Other income, net	6	80
Income before provision for income taxes	1,198	1,984
Provision for income taxes	430	640
Net income	768	1,344
Net income per common share:
Basic	$ 0.09	$ 0.16
Diluted	$ 0.09	$ 0.16
Average shares outstanding:
Basic	8,378,247	8,304,484
Diluted	8,544,052	8,503,101
Comprehensive Income
Net income	768	1,344
Other comprehensive income (loss):
Foreign currency translation adjustment	(594)	331
Change in market value of marketable securities	327	(183)
Deferred tax effect of change in marketable securities	(119)	66
Total other comprehensive (loss) income	(386)	214
Comprehensive income	$ 382	$ 1,558