16. Other Comprehensive Income (Loss) (Details) - Schedule of Accumulated Other Comprehensive Income (Loss) - USD ($) $ in Thousands		12 Months Ended
		Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2015
Schedule of Accumulated Other Comprehensive Income (Loss) [Abstract]
Balance, Change in Market Value of Marketable Securities		$ 1,167	$ 812	$ 985
Balance, Foreign Currency Translation Adjustment		1,114	1,152	1,905
Balance, Total		2,281	1,964	$ 2,890
Items of other comprehensive income (loss) before reclassification, pretax, Change in Market Value of Marketable Securities		534	(150)
Items of other comprehensive income (loss) before reclassification, pretax, Foreign Currency Translation Adjustment		(38)	(753)
Items of other comprehensive income (loss) before reclassification, pretax, Total		496	(903)
Tax effect - Change in Market Value of Marketable Securities		(182)	51
Tax effect - Foreign Currency Transalation Adjustment		0	0
Tax effect - Total		(182)	51
Items of other comprehensive income (loss)before reclassification, net of taxes, Market Value of Marketable Securities		352	(99)
Items of other comprehensive income (loss)before reclassification, net of taxes, Foreign Currency Translation Adjustment		(38)	(753)
Items of other comprehensive income (loss)before reclassification, net of taxes, Total		314	(852)
Reclassification adjustments, pretax - Marketable Securities	[1]	28	(131)
Tax - Marketable Securities		(25)	57
Tax effect - Change in Market Value of Marketable Securities		3	(74)
Tax effect - Total		3	(74)
Total other comprehensive income (loss), net of taxes, Marketable Securities		355	(173)
Total other comprehensive income (loss), net of taxes, Foreign Currency Transalation Adjustment		(38)	(753)
Total other comprehensive income (loss), net of taxes, Total		$ 317	$ (926)

[1] The reclassification adjustments represent net realized gains on the sale or redemption of available-for-sale marketable securities that were reclassified from AOCI to Other income (expense), net.