Share-Based Payments - Summary of Warrant Activity (Details) - Warrant [Member] - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Jan. 31, 2017	Apr. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of Shares, Beginning Balance	2,109,840
Number of Shares, Granted	0
Number of Shares, Exercised	0
Number of Shares, Expired	0
Number of Shares, Ending Balance	2,109,840	2,109,840
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted Average Exercise Price, Beginning Balance (in usd per share)	$ 5.54
Weighted Average Exercise Price, Granted (in usd per share)	0
Weighted Average Exercise Price, Exercised (in usd per share)	0
Weighted Average Exercise Price, Expired (in usd per share)	0
Weighted Average Exercise Price, Ending Balance (in usd per share)	$ 5.54	$ 5.54
Weighted Average Remaining Contractual Life (in years)	2 years 10 months 24 days	3 years 7 months 6 days
Aggregate Intrinsic Value, Beginning Balance	$ 0
Aggregate Intrinsic Value, Ending Balance	$ 0	$ 0