Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jan. 31, 2017	Apr. 30, 2016
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 1,537	$ 2,362
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	83,848,563	82,269,748
Common stock, shares outstanding	83,648,563	82,069,748
Treasury stock, shares	200,000	200,000