Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jan. 31, 2016	Apr. 30, 2015
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 2,713	$ 3,992
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	81,673,833	80,346,488
Common stock, shares outstanding	81,473,833	80,146,488
Treasury stock, shares	200,000	200,000