Basis of Presentation, Business and Summary of Significant Accounting Policies - Treasury Stock (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Jan. 31, 2016	Apr. 30, 2016
Treasury Stock
Shares repurchased, cost		$ 5,827
Proceeds from reissuance of treasury stock	$ 4,856
Decrease to Retained earnings (accumulated deficit) for difference between cost of treasury stock and proceeds from reissuance	$ 971
Treasury Stock
Treasury Stock
Number of shares repurchased	394,577	394,577
Shares repurchased, cost	$ 5,827	$ 5,827
Shares reissued		394,577